Meg Ryan played Betsy Stewart Montgomery Andropoulos from 1982 to 1984 on "As the World Turns."
Sarah Michelle Gellar of "Buffy the Vampire Slayer" fame was on "All My Children" as Erica Kane's manipulative daughter, Kendall Hart, from 1993 to 1995.
Before playing conniving Gabrielle on "Desperate Housewives," Eva Longoria once played psychotic Isabella Brana Williams on "The Young and the Restless" from 2001 to 2003.
Demi Moore played Jackie Templeton, an enterprising reporter, on "General Hospital" from 1982 to 1983 before blowing up in 1990 after co-starring with Patrick Swayze in "Ghost."
David Hasselhoff played Dr. William "Snapper" Foster Jr. on the "Young and the Restless" from 1975 to 1982. He also reprised the character on the show for a short arc that aired in mid-June 2010.
At 10 years old, Lindsay Lohan was a semi-regular on "Another World" playing Alexandra "Alli" Fowler from 1996 to 1998.
Mark Hamill, better known as Luke Skywalker of "Star Wars," played Kent Murray on "General Hospital" from 1972 to 1973.
For many TV viewers, Kelly Ripa will always be Hayley Vaughn Santos, the character she played on "All My Children" from 1990 to 2002.
Marg Helgenberger of "CSI" fame was on "Ryan's Hope" as Siobhan Ryan, a feisty rookie police officer, from 1982 to 1986.
Before playing Bree Van de Kamp on "Desperate Housewives," Marcia Cross cut her teeth in daytime TV on "The Edge of Night," "Another World" and "One Life to Live" in 1986 and 1987.
John Stamos played bad boy Blackie Parrish on "General Hospital" before he was Uncle Jesse on "Full House."
Josh Duhamel is better known these days as Mr. Fergie and for the "Transformers" movies, but he once made Pine Valley his home as Leo du Pres on "All My Children" from 1994 to 2002.
Oscar-nominated and Emmy-winning actor Laurence Fishburne started out his career by playing street kid Joshua Hall on "One Life to Live" between 1973 and 1976.
Before he was Dr. Frasier Crane on "Cheers" and "Frasier," Kelsey Grammer was Dr. Canard on the NBC soap "Another World." The Julliard-trained actor played the role only for less than a year in 1984.
Before Ricky Martin was "Livin' La Vida Loca," he was Port Charles' resident hottie Miguel Morez on "General Hospital" from 1994 to 1995.
Just two years after graduating from Harvard, future Oscar-winner Tommy Lee Jones played brooding bad seed Dr. Mark Toland on "One Life to Live." He played the character from 1971 until he was killed off in 1975.
Oscar-winner Susan Sarandon started out her career as a model, but soon found her way to television, first starring as Patrice Kahlman from 1970 to 1971 on "A World Apart." She next played murderous drifter Sarah Fairbanks on "Search for Tomorrow" in 1972.
A four-time Academy Award nominee, Julianne Moore showed a flair for drama early on in her career, taking on the dual roles of half-sisters Frannie and Sabrina Hughes on "As the World Turns." Her stint on the show in 1985-88 even won her a Daytime Emmy.
Ryan Phillippe got his acting career off on groundbreaking terms, playing Billy Douglas from 1992 to 1993 on "One Life to Live." The character was the first gay teenager every to be portrayed on a daytime soap opera.
Tom Selleck, sans his famous moustache, played Jed Andrews on "The Young and the Restless" from 1974 to 1975 before going on to fame as private investigator "Magnum, P.I."
You might already know that one of Leonardo DiCaprio's early roles was on the sitcom "Growing Pains." But even before then, Leo played Mason Capwell in 1990 on the soap opera "Santa Barbara."
Again, many fans know that Brad Pitt caught audiences' eye with a small part in 1991's "Thelma & Louise," but not many realize before that he had a bit part in 1987 on "Another World."
Marisa Tomei's ditzy "As the World Turns" character Marcy Thompson had quite the busy life. From 1983 to 1985, Tomei inhabited a character who accused one man of sexual harassment before finding a prince to marry and living happily ever after.
It may be hard to imagine that "Goodfellas" star Ray Liotta got his start in soaps, but that's exactly what he did, playing fan favorite Joey Perrini on "Another World" from 1978 to 1981.
Although he had a small role in "National Lampoon's Animal House," Kevin Bacon was far from a star when he landed his TV debut in 1979 on the soap "Search for Tomorrow." But he wasn't done yet. He went on to play a troubled teen on "Guiding Light" from 1980 to 1981 before finding fame as a dancing fool in "Footloose."
While other future stars were content with playing one soap opera doctor, that wasn't good enough for James Earl Jones. Before finding fame by voicing Darth Vader in "Star Wars," Jones played Dr. Jerry Turner on "As the World Turns" and then Dr. Jim Frazier on "The Guiding Light," both in 1966.
Kathleen Turner got her big break at the age of 23 with a role on the soap opera "The Doctors." Turner played trampy Nola Dancy from 1978 to 1979.
After a stint on "The Love Boat" in 1985-86, Teri Hatcher was cast on the daytime soap "Capitol" as congressman's wife Angelica Clegg. However, she only stuck around for about a year before moving on.
Decades before he became J.R. Ewing, and even before he was astronaut Maj. Tony Nelson on "I Dream of Jeannie," Larry Hagman got his start in 1957 playing Curt Williams on "Search for Tomorrow." He followed that up by playing lawyer Ed Gibson on "The Edge of Night" from 1961 to 1963.
Before he became known as Superman, Christopher Reeve played Ben Harper on "Love of Life" from 1974 to 1976.
Nearly a decade before becoming "Ally McBeal," Calista Flockhart spent the spring of 1989 making her first television appearance with a minor role as a babysitter in an episode of "Guiding Light."
Melina Kanakaredes played Eleni Andros on "Guiding Light" before she solved crimes as Det. Stella Bonasera on "CSI: NY."
"The Biggest Loser" host Alison Sweeney continues the role she started in 1993 as Salem's resident bad girl, Sami Brady on "Days of Our Lives."
Actress Tori Spelling recently spoke publically about her husband and fellow actor Dean McDermott's affair. But he's not the first celebrity to get in hot water over extramarital activities. Check out this list of high-profile celebrity affairs.