KO,[1] formerly known as Karen Olivo, (born August 7, 1976) is an American stage and television actor, theater educator, and singer.

The following year, they won the 2009 Tony Award for Best Featured Actress in a Musical for their performance as Anita in a revival of West Side Story.

In late 1998, KO began playing Mimi on the tour, and they continued in the role until leaving the show in January 1999.

They moved back to New York City in 1999[4] but did not receive any roles outside of a small part in As the World Turns before joining the regional try-out of the musical Brooklyn in 2003.

[9] Following its closure, KO joined the cast of the Brazilian-themed off-Broadway musical Miracle Brothers, which closed in October 2005.

Written by Pulitzer Prize-winning playwright Lynn Nottage, the play "draws upon the screwball films of the 1930s to take a funny and irreverent look at racial stereotypes in Hollywood.

They played wealthy law student Giada Cabrini, a potential love interest of firm partner Will Gardner (Josh Charles).

KO was a series regular in the second season of NBC's Harry's Law, playing "hot shot lawyer" Cassie Reynolds hired by Kathy Bates' character.

[16] KO also appeared as Isabelle Perez, a woman who was unknowingly sterilized in the Law & Order episode "Birthright".

They also appear in the spin-off series Law & Order: Special Victims Unit as Jennifer Benitez in an episode titled "Loophole".

They later appeared in Law & Order: Special Victims Unit as Yelina Muñoz in an episode titled "October Surprise".

[24] On April 14, 2021, KO announced they would not return to the show once it reopens as a protest of the industry's silence on the allegations against producer Scott Rudin.

[26] The world premiere was set to open in May 2022 at Signature Theatre in Arlington, Virginia, but was cancelled due to the COVID-19 pandemic.