Helen Rachel Slater (née Schlachter, born December 15, 1963) is an American film actor and singer-songwriter.

Slater was born in Massapequa, New York of Jewish heritage. Her parents are Gerald and Alice Joan Slater who divorced in 1974. Her mother, Alice, is a left-wing nuclear disarmament lobbyist based in New York. She also has a brother, David, who is a lawyer in New York City.

Helen attended the New York High School of Performing Arts, graduating in 1982. She is an accomplished pianist and in 2004 released her first album One of These Days through her own record label Landsleit Records. In 2005, she followed it up with her second album Crossword.

She co-founded the New York theater group, The Naked Angels, with Gina Gershon. In 1990, she married award-winning editor Robert Watzke. Their daughter, Hannah Nika, was born August 28, 1995, weighing 7lb 10oz.

Having made her actress debut in the after school special, Amy and the Angel (1982) (TV) starring alongside James Earl Jones, and Matthew Modine, she took the acting bug very seriously. This was also the only film she appeared in as a brunette. Within months of her graduating, she attended auditions for an upcoming spin-off of the famous Superman (1978) franchise. The film was to be shot in England at the Pinewood studios, where the first films were filmed. Slater even spoke to Christopher Reeve at the time of the auditions about playing a superhero to assure herself she could do it. After being the first to present herself for audition, she was cast in the film, Supergirl (1984) and her career took flight. Although Supergirl received mixed reviews at its opening, most critics were impressed with her abilities to perform. In fact, most critics considered that she did a better job at keeping a secret identity (a mousy school girl) than Christopher Reeve did as Clark Kent.

In her next film, she was cast as a modern day Joan of Arc in the ignored, yet cult classic The Legend of Billie Jean (1985). She was cast alongside Christian Slater (no relation), and Yeardley Smith. Next, she went the comic route. She starred in the two big comic blockbusters, Ruthless People (1986) and The Secret of My Success (1987). She received praise for both roles and finally attained status as a professional actress.

Next, she and her friend Melanie Mayron starred in the feminist comedy film Sticky Fingers (1988). The film was ignored by the masses but gained respect from the critics. It was this film and her next, Happy Together (1989/I), that she was able to prove that she could do comedy as well as drama. She has also appeared in A House in the Hills (1993), in which she appeared nude, as well as done the voiceover for Talia in Batman: The Animated Series (1992).

Slater's regional stage credits include appearances in such as Grease, and Shakespeare and Friends. Off-Broadway, she starred in Responsible Parties and Almost Romance. She also attended classes at both NYU and UCLA, trying to broaden her acting abilities.

She attempted a regular berth on the short-lived ABC drama Capital News (1990), as a novice newspaper reporter. Slater, who was also in the cast of Linda Yellen's improvisational TV-movies Chantilly Lace (Showtime, 1993) and Parallel Lives (Showtime, 1994), has continued to act onstage. She has appeared in Caroline in the City, Seinfeld, Law & Order: Special Victims Unit as well as many others. She also became a spokeswoman for Preference by L'oreal in both TV and print ads.

Slater has stated that she pursued musical efforts even before doing movies. In the 1989 movie Happy Together she sung a medley of Broadway songs as well other songs. In the 1994 movie Lassie she also sung as well. For the soundtrack of the film Nowhere In Sight (2000), she contributed the song The Detour.

In 2003 she released a CD, One Of These Days, consisting of her original songs. Notably, the tracks were real-time recordings with Slater singing and playing piano, plus six other musicians total; no multitracking, editing, or dubbing were employed.

In 2005, she released a second CD, Crossword, using the same recording approach as the first CD.