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: Upon graduating from the University of Minnesota, Peter MacNicol traveled the length and breadth of the U.S. as a regional repertory actor. In his first film, Dragonslayer (1981), MacNicol essayed one of his few leading-man roles as Galen, a hapless assistant sorcerer who makes good. His most celebrated film assignment was as Stingo, the innocent-bystander narrator of Sophie's Choice. Most of the time, MacNicol has been seen in comical, sycophantic roles, such as the easily demonized Janocz in Ghostbusters II (1989) and the unctuous camp counselor in Addams Family Values (1993). On television, Peter MacNicol starred in the brief Norman Lear political lampoon The Powers That Be (1992) and co-starred as Alan Birch on the CBS medical drama Chicago Hope (1994).MacNicol continued to play small but indelible roles in a variety of small but indelible films throughout the mid-'90s. There was 1992's underrated Housesitter with Goldie Hawn and Steve Martin; acclaimed director Mel Brooks' Dracula: Dead and Loving It (1995); and a starring role opposite cult comedian Rowan Atkinson in 1997's Bean. Despite his respectable feature-film success, however, MacNicol wouldn't get solid mainstream recognition until the 1997 debut of Ally McBeal. The show featured MacNicol as John Cage, an immensely insecure but highly gifted lawyer whose lovable, if over-sensitive, nature tugged at the heartstrings of Ally (Calista Flockhart) and television audiences alike. MacNicol remained a lead character on the show from 1997 to 2002, and was able to participate not just as an actor, but also as a director, screenwriter, and amateur karaoke singer. No longer the affable John Cage, MacNicol could be seen assigning Jamie Foxx the unpleasant task of letting his employees know of a rapidly approaching downsizing in 2004's Breakin' All the Rules. Recurring roles on Numbers and 24 as well as voice work in such animated shows as Harvey Birdman, Attorney at Law, The Batman, The Spectacular Spider-Man helped MacNicol maintain a high profile in the following years, and in 2012 he could be seen as the Secretary of Defense in the big-budget game board adaptaion Battleship.

Trivia: Began singing with the San Diego Children's Choir at age 6. Attended summer camp at the La Jolla Playhouse. Performed in La Boheme with the San Diego Opera at age 10. Spent two years and had four screen tests before he was cast in Big Time Rush in 2009. As part of Big Time Rush, released his first studio album, BTR, in 2010. Toured with fellow Nickelodeon star Victoria Justice on the Summer Break Tour in 2013. Appeared on Dancing with the Stars in 2014, partnered with Peta Murgatroyd.