This year marks the 20th season of Law & Order, the long-running NBC crime drama that's played host to hundreds of guest stars over the years. Many of those guest stars were relative unknowns when they appeared on the show, but went on to become household names. Here are some of our favorites.
Subterranean Homeboy Blues (1990)
Most Famous Role Since: Miranda Hobbes on Sex & the City
Everyone remembers Nixon's recent Emmy-winning role on Law & Order: SVU, where she played a crazed Russian woman, but her relationship with the show started long ago. Nixon first appeared on Law & Order in 1990, when she played a manipulative murderer in the show's second-ever episode. Her character claimed self-defense after shooting two black men on the New York City subway.
The Violence of Summer (1991)
Most Famous Role Since: Truman Capote in Capote
Before Capote, The Talented Mr. Ripley, and even Scent of a Woman, Philip Seymour Hoffman played a drug dealer accused of raping a celebrity journalist on Law & Order. Hoffman's role on the crime drama marked his first-ever on-screen performance, according to IMDB.
Conduct Unbecoming (1993)
Most Famous Role Since: Nurse Carol Hathaway on ER
Before going on to earn Emmy and Golden Globe recognition for her work on ER, Margulies played a one-time part as a lieutenant on Law & Order. In "Conduct Unbecoming," the team investigates the death of a female Naval officer during a party in a Manhattan hotel.
Star Struck (1992), Ann Madsen in Old Friends (1994)
Most Famous Role Since: C.J. Cregg on The West Wing
Before she advised the President on The West Wing, Janney played two parts on Law & Order. In her 1994 appearance, she played a reluctant witness against a member of the Russian mob.
Most Famous Role Since: Sydney Bristow on Alias
For her 1996 appearance on Law & Order, Garner played the college-aged mistress of a police detective. She later moved on to guest spots on shows like Spin City before landing the lead role on the spy drama Alias.
Savior (1996), Laura Kendrick in Fools for Love (2000)
Most Famous Role Since Meredith Grey on Grey's Anatomy
Before she became a TV doctor, Ellen Pompeo played two not-all-that-different roles as a girl complicit in the murder of her mother and a girl complicit in the murder of her sister.
Law & Order airs Friday nights at 8 pm on NBC.