Trivia: Born on a Belgian army base, curly brown-haired Johnny Galecki grew up in Chicago and started acting professionally at the age of 12. He made his feature film debut in 1988 as River Phoenix's little brother in A Night in the Life of Jimmy Reardon. He then assumed the role of Rusty Griswold in National Lampoon's Christmas Vacation, and gained his first regular role on a TV series as Robert Ulrich's son in American Dreamer. In 1991, he starred in the made-for-TV movie Backfield in Motion, co-starring the production team of Roseanne and Tom Arnold. The next year, Galecki joined the cast of Roseanne as Darlene's sensitive and put-upon boyfriend David Healy. He stayed on the show until its final season in 1997, although he wasn't on very much during its last few years. His other television credits include several guest appearances, leading roles in made-for-TV movies, and a part on the short-lived Head of the Class spin-off Billy. After Roseanne ended, he got back into features with small parts in I Know What You Did Last Summer, Bean, and Suicide Kings. He continued playing slightly effeminate sensitive males in The Opposite of Sex and Morgan's Ferry. After bit parts in Bounce, Playing Mona Lisa, and Vanilla Sky, Galecki played a leading role in the comedy thriller Bookies, which premiered at the 2003 Sundance Film Festival. In 2007 he landed the leading role in the sitcom The Big Bang Theory and it grew to be one of the most popular shows on TV, earning Galecki Emmy, Golden Globe, and Sag nominations in 2011 for his work on the show. He maintained his movie career in projects such as Hancock and In Time.

Trivia: Kaley Cuoco began modeling and acting at the tender age of six, when she was cast in the TV movie Quicksand: No Escape. Growing up in front of the camera, the young actress continued to appear as the requisite little girl in movies like Virtuosity and Picture Perfect until she was cast as teenage daughter Bridget on the sitcom 8 Simple Rules. TV would prove to be the actor's bread and butter, and she would go on to star on Charmed, 6Teen, and Monster Allergy, not to mention The Big Bang Theory, a show that earned her legions of fans as Penny, the hot neighbor of two geeky physicists (Johnny Galecki, Jim Parsons). Cuoco also continued to appear in films, though on a much smaller scale compared to her TV work. She appeared in a supporting role in the Easter film Hop in 2011, and played the female lead opposite Kevin Hart and Josh Gad in The Wedding Ringer in 2015.

Trivia: Though initially typecast in comedic roles -- including a small turn in Old School (2003), a contribution to Tracey Ullman in The Trailer Tales (2003), and work on MADtv -- American character actor Simon Helberg quickly branched out into diverse genres. He appeared as a CBS page in George Clooney's revered Edward R. Murrow biopic Good Night, and Good Luck., as a junior agent in Christopher Guest's For Your Consideration (2006), and in a recurring role on the Aaron Sorkin comedy drama Studio 60 on the Sunset Strip. In 2007, Helberg was cast in the regular role of Howard Wolowitz on the sitcom The Big Bang Theory, about a couple of nerdy physicists (Johnny Galecki and Jim Parsons) who struggle with women, and everything else outside the lab. In 2007, Helberg also made appearances in the comedies Mama's Boy and Walk Hard: The Dewey Cox Story. He played a young rabbi in the Coen brothers film A Serious Man (2009), and continued to make guest appearances on TV shows such as Kick Buttowski: Suburban Daredevil and Drunk History, while maintaining his regular status on The Big Bang Theory.

Trivia: Actor Kunal Nayyar first made a splash in Hollywood playing physicist Koothrappali on the series The Big Bang Theory, which debuted on CBS in 2007. In 2012 Nayyar voiced the character of Gupta in Ice Age: Continental Drift, and the following year he could be seen opposite Gina Gershon and Billy Campbell in the thriller, The Scribbler. In addition to his feature work Nayyar also co-wrote the critically acclaimed play Cotton Candy, which runs in New Delhi.

Trivia: Name means "water" in Hebrew. Had her big break in the 1988 film Beaches, playing the younger version of Bette Midler. Appeared in the music video for Michael Jackson's "Liberian Girl." Made her television debut in the 1980s fantasy series Beauty and the Beast. Best known for her role as the title character in the sitcom Blossom. Was successful in many voiceover roles in animated series, including Kim Possible and Hey Arnold! Appeared on a 2009 episode of What Not To Wear. Her The Big Bang Theory character, Amy Farrah Fowler, is a neurobiologist, corresponding to Bialik's real-life degrees in neuroscience. Is a spokesperson for the Holistic Moms Network and gave birth to her second son at home.

Trivia: Began her career as a comedian and had a one-woman show, The Miss Education of Jenna Bush, in which she played the daughter of former president George W. Bush. Co-wrote, directed and starred in the comedic short The Condom Killer. Toured with the political-satire group Gross National Product. Performs with The Realest Real Housewives show, in which comedians read transcripts from the Real Housewives franchise. Was a recurring guest star on series 3 of The Big Bang Theory before joining the cast as a series regular in series 4.

Trivia: Like Henry Thomas and a few others of the same generation, Jerry O'Connell proves that second acts are far from impossible for Hollywood actors who began their careers as children. O'Connell first gained recognition among film fans as "that fat kid from Stand By Me," when he starred in the 1986 Rob Reiner film at the age of eleven - then experienced a massive physical transformation. Several years and many lost pounds later, O'Connell emerged as a tall, handsome screen lothario, a development that provoked substantial commentary from both film critics and any number of lay viewers.Born in New York City on February 17, 1974, O'Connell enrolled in acting classes at the age of six. He obtained his first professional assignments acting in commercials when he was ten, and a year later made his film debut in the critically acclaimed Stand By Me. Though somewhat overshadowed by the presence of teen idol co-stars River Phoenix and Corey Feldman, O'Connell still managed to win a place in the coming-of-age pantheon. After Stand By Me, he appeared in the memorable syndicated television series My Secret Identity (as a high schooler with superpowers) and enrolled at Manhattan's Professional Children's School. Following his graduation, he attended New York University, where he attained a B.A. in Film and Television in 1995. While still an NYU student, O'Connell appeared in the eminently forgettable Jason Priestley vehicle Calendar Girl (1993).After his college graduation, O'Connell began to pursue thesping full-time. He soon landed a starring role on the sci-fi series Sliders, which, despite low ratings, had a very loyal viewership. In 1996, the actor's popularity grew beyond the confines of television when he starred in both Joe's Apartment and Jerry Maguire. The latter film was a particular success, and O'Connell began to land steady film assignments once again. Next up was the slasher movie Scream 2 (1997), in which he played Neve Campbell's boyfriend. After an uncredited role in the Jennifer Love Hewitt vehicle Can't Hardly Wait (1998), O'Connell returned to television to star as a young Vietnam War soldier in the miniseries The '60s in 1999. That same year, he starred as a neanderthal-like jock in Body Shots, a film about the search for love and/or a lay amongst a group of Los Angeles twentysomethings.At this point, if O'Connell still carried a full resume, he often seemed to alternate between respectable A-list material - such as the disappointing but ambitious Brian De Palma sci-fi'er Mission to Mars (2000) and the generally pleasant family comedy Yours, Mine and Ours (2005) - and ridiculous studio dreck, such as the misogynistic sex comedy Tomcats (2001) and the awful 2002 "family" picture Kangaroo Jack (where the actor co-starred alongside a wisecracking CG-animated marsupial). In fall 2007, O'Connell trekked back to the small screen for one of the three lead roles in the sitcom Carpoolers - about a cadre of male buddies who share rides to and from work each day. O'Connell would spend the next few years appearing in movies like Obsessed and Piranha, in addition to successful TV runs like Do Not Disturb and The Defenders.O'Connell married supermodel and actress Rebecca Romijn in 2007. The two have two children.

Trivia: Actor Robert Wu began his career in the late '90s, and built up his resumé by working steadily through the new millennium, appearing in low-profile films like Kung Phooey! and Painted Angels. After appearing in the Courteney Cox Arquette thriller November in 2004, Wu did some television work on shows like The Shield before signing on for Nanking, Bill Guttentag's documentary about the 1937 massacre of the Chinese city.