LOS ANGELES (AP) - Ellen DeGeneres and longtime girlfriend Portia de Rossi are jumping at the chance to get married.

DeGeneres announced their engagement during a Thursday taping of "The Ellen DeGeneres Show," telling the studio audience the news that the California Supreme Court had struck down state laws against gay marriage.

"So I would like to say now, for the first time, I am announcing: I am getting married," she said during the show, airing Friday.

The studio audience leapt to its feet for a long ovation, and De Rossi ("Ally McBeal," "Nip/Tuck") was sitting in the audience, beaming and clapping.

Then DeGeneres cracked: "Thank you. I'll tell you who the lucky guy is soon."

The court ruling means same-sex couples could tie the knot in as little as a month. However, religious and social conservatives are seeking to put a constitutional amendment on the ballot in November that would undo the Supreme Court ruling and ban gay marriage.

DeGeneres, 50, has boldly used TV before to make a stand for gay rights.

In 1997, she brought her character on the ABC sitcom "Ellen" out of the closet, making the show the first on prime-time network TV to have an openly gay lead. The move drew cheers from gay civil rights organizations but was condemned by some religious groups.

A month before, DeGeneres had proclaimed from the cover of Time magazine that she was a lesbian.

DeGeneres, 50, and the glamorous de Rossi, 35, have been a familiar couple at Hollywood events, including the Academy Awards. Previously, DeGeneres had a high-profile relationship with actress Anne Heche.

In a 2005 interview with Allure magazine, the comedian said she hoped she and de Rossi are "together the rest of our lives."

"I never would have thought my life would have turned out this way," DeGeneres told the magazine. "To have money. Or to have a gorgeous girlfriend. I just feel so lucky with everything in my life right now."

(Copyright 2008 by The Associated Press. All Rights Reserved.)