Trivia: Actor Mark Harmon is the son of football great Tom Harmon and 1940s film star Elyse Knox; he is the brother of Kris Harmon -- ex-wife of Ricky Nelson -- and uncle of Kris and Ricky's actress daughter Tracy Nelson; and finally, Harmon is the husband of Mork and Mindy star Pam Dawber. Harmon emulated his dad by playing football at UCLA, then followed in mom's footsteps by turning to acting; his first movie was 1978's Comes a Horseman. Most of Harmon's starring film appearances are easy to take but unmemorable, such as his lackadaisical high-school teacher in Summer School (1988). A baseball fan, Harmon was once part-owner of the minor-league San Bernardino Spirit, a team which figured prominently in his 1988 film vehicle Stealing Home. Harmon is best known for his work on 1980s series TV: he has co-starred in Flamingo Road and Moonlighting, and played the lead role of AIDs-stricken Dr. Bob Calswell on St. Elsewhere. TV would prove to be a source of success for the actor, and he would go on to star on such popular shows as Chicago Hope and NCIS.

Trivia: David McCallum's parents were both members of the London Philharmonic; his mother was a cellist and his father was first violinist. The young Scots-born McCallum himself planned to pursue a musical career after serving with the Royal West African Frontier Force, but decided instead upon acting. Following his studies at the RADA, McCallum entered films in 1957, where he was usually cast as a troublemaking street punk or callow junior officer. His first American film (albeit lensed principally in England) was Freud (1962), in which he played a profoundly mother-obsessed mental patient. McCallum became the rage of the teeny-bopper set when he was cast as cool-headed Russian secret agent Ilya Kuryakin on TV's The Man From UNCLE (1964-68). At one point, McCallum was receiving far more fan mail than the series' ostensible star, Robert Vaughn; he took advantage of his celebrity to launch a brief singing career, duetting with Nancy Sinatra on the 1966 UNCLE episode "The Take Me to Your Leader Affair." He also wrote the music and lyrics and sang the title song of his 1967 movie vehicle Three Bites of the Apple. Following UNCLE, McCallum had a handful of solid dramatic film roles before returning to the small screen in the short-lived 1975 series The Invisible Man. He continued to appear primarily in episodic television, although he occasionally could be glimpsed on the big-screen as well. Highlights include The Watcher in the Woods, Matlock, The Wind, Murder She Wrote, and The A-Team. The nineties began with a major part in the sleeper Hear My Song, before continuing in Healer, Law and Order, and Cherry. McCallum became a fixture on television yet again at the beginning of the 21st century when he was cast as Donald "Ducky" Mallard on CBS' drama NCIS, which was for a time the top-rated scripted drama on network television.A man of sundry outside interests, McCallum's range of expertise includes computers and small-arms weaponry. Once wed to actress Jill Ireland, David McCallum has since 1967 been married to Katherine Carpenter.

Trivia: Going under the name Pauley P., actress Pauley Perrette (born March 27th, 1969) first gained notoriety with an extended arc on the acclaimed ABC drama Murder One. She followed that with guest spots on such shows as The Drew Carey Show and Frasier before landing a gig as a regular (using her full moniker) on the short-lived Party of Five spin-off Time of Your Life. After that series bowed, Perrette could be seen in small capacity in the big-screen hits Almost Famous and The Ring. In 2003, she finally landed in a series with staying power. This time it was the JAG spin-off Navy NCIS, a CBS drama that cast Perrette in a lead role alongside Mark Harmon.

Trivia: Actor Sean Murray began filling up his resumé when he was just a young teenager, making small appearances in movies like Hocus Pocus and This Boy's Life. He continued to steadily wrack up small and midsized roles in films and on television until 2004, when he joined the cast of the series NCIS playing Timothy McGee. His stepsister, Troian Bellisario, has appeared in NCIS as Murray's character's sister.

Trivia: A graduate of the famous School for the Performing Arts, actor Rocky Carroll continued his studies at the Conservatory of Theatre Arts at Webster University before moving to New York in the mid-'80s to try his hand at a professional acting career. He soon found success with the Shakespeare on Broadway series, and cultivated a flourishing career on-stage. Carroll also branched into screen acting, with recurring roles on Roc and Chicago Hope, and in movies like Crimson Tide, Born on the Fourth of July, and Yes Man.

Trivia: A graduate of Colorado's Niwot High School, actor Brian Dietzen gravitated to drama at eight years old, when he caught the acting bug from an elementary school play; in time, he extended his stage activities into high-school productions, and attended the University of Colorado at Boulder as a theater major in that institution's B.F.A. program. Under the mentorship of Sean Kelley, Dietzen formally trained in theatrical mainstays -- from Waiting for Godot to Equus; so successful were his efforts in these productions that it prompted him to join the Colorado Shakespeare Festival after graduation, and then to make the big leap to Los Angeles. Dietzen scored his first major coup in L.A. by signing on for a regular role in the short-lived WB series My Guide to Becoming a Rock Star, and then landed a small part in the American Idol spin-off movie From Justin to Kelly (2003). The actor is best known, however, for his recurring series role as Jimmy Palmer, assistant lab technician to Donald "Ducky" Mallard (David McCallum), on the popular CBS procedural thriller NCIS. On the side, he remained extremely active in stage work.

Trivia: Dropped out of college and took public speaking classes to help further her career. At the premiere of Gone (2012) she admitted she's always had a fear of being kidnapped. Was cast in NCIS in 2013 as a replacement for the departing Cote de Pablo; she was promoted to a series regular before her first episode aired.

Trivia: In his role as eager-to-fit-in exchange student Fez on the enduring and popular Fox sitcom That '70s Show, actor Wilmer Valderrama mangled the popular lingo of the eponymous decade with gleeful abandon. Though removed from his small-screen persona, the handsome actor can give the impression of a young Benicio Del Toro. His dorky and personable charm as Fez endeared him to television audiences, making him one of That '70s Show's defining personalities. Born January 30th, 1980, Valderrama is a Miami native whose family relocated to Venezuela when he was three years old; the aspiring actor would eventually return stateside to pursue a career in the entertainment industry. Valderrama joined the cast of That '70s Show shortly before finishing his high-school education at William Howard Taft High School in 1998, and three short years later, the television mainstay made his feature debut by taking to the diamond with a supporting role in the romantic teen comedy Summer Catch. Guest appearances on Grounded for Life and That '70s Show co-star Ashton Kutcher's hidden-camera prankster series, Punk'd, were quick to follow, and in 2003, Valderrama essayed the role of DJ Keoke in the flashy true-crime drama Party Monster. Based on the exploits of murderous club-kid Michael Alig, the film offered Valderrama an opportunity to truly separate himself from his popular small-screen persona. With That '70s Show still going strong in 2004, the popular television star's voice could also be heard in the animated children's film Clifford's Really Big Movie. 2006 found the actor playing a small supporting role for the scathing message movie Fast Food Nation, and took on the role of Detective Efrem Vega for the NBC television series Awake.Valderrama continued to concentrate on TV, booking guest arcs on shows like Suburgatory and Raising Hope before settling into more stable work with regular gigs on From Dusk till Dawn: The Series and the short-lived Minority Report series. In 2016, he joined the cast of NCIS for the 14th season of the show.

Trivia: A budding TV star, Jennifer Esposito (born April 11th, 1973) opted to focus more exclusively on movies after landing one of the lead roles in Spike Lee's incendiary Summer of Sam (1999). A native New Yorker, Esposito trained at the Lee Strasberg Institute and worked on TV in the early 1990s, including a recurring role on New York Undercover. Following small roles in indie films Kiss Me, Guido (1997) and A Brother's Kiss (1997), Esposito gained prime time notice in 1997 as Michael J. Fox's sassy "Noo Yawk" secretary on ABC's hit sitcom Spin City. During her two seasons on the show, Esposito also appeared in Edward Burns' blue collar romance No Looking Back (1998), the teen slasher sequel I Still Know What You Did Last Summer (1998), and Spike Lee's basketball drama He Got Game (1998). After playing the more substantial dramatic part of Adrien Brody's punk singer girlfriend in Summer of Sam, however, Esposito left Spin City in 1999. Dividing critics and audiences over its dicey slice of New York City 1977 life and Lee's visual pyrotechnics, Summer of Sam failed at the box office. Esposito next appeared as one of Chris O'Donnell's ex-girlfriends in The Bachelor (1999). The millennial turnover found the beautiful rising starlet establishing herself as a versatile actress in such efforts as Dracula 2000 (2000) and Don't Say a Word (2001), and after appearing alongside Dana Carvey in the family comedy The Master of Disguise (2002), Esposito joined an impressive cast including Luis Guzman, William H. Macy and George Cloony for the caper comedy Welcome to Collinwood (also 2002). In 2004, Esposito took on a role as the long-suffering supervisor of a bumbling police officer in the less than successful comedy Taxi. The following year, however, her luck would change when she joined the cast of filmmaker Paul Haggis' Academy Award-winning drama Crash, in which she played the girlfriend and partner of an emotionally distant police officer. Afterwards, the actress joined several television shows including FX's drama Rescue Me, in which she worked alongside the show's star Denis Leary, and also appeared in ABC's comedy Samantha Who?, NBC's medical drama Mercy and CBS's cop procedural Blue Bloods.

Trivia: Aspired to be an actor from the age of 5. Moved to London at the age of 17 to pursue his acting career. Was homeless for a short time while searching for work as an actor. Appeared in numerous British television series, including Law & Order: UK, Doctor Who, The Cut and Doctors. Nominated for BAFTA's Screen Nation Award for Best Emerging Talent in 2010. In 2013, moved to Los Angeles in hopes of furthering his acting career. Starred in a 2015 TV commercial for Lexus.