One of the world’s best-known lesbians will announce on her show today that she intends to take advantage of the ruling of the California Supreme Court striking down a  ban on gay marriage.

Gay and lesbian couples in America’s most populous state could be having legal civil marriage ceremonies in one month.

Ellen DeGeneres made the announcement during the taping of her talk show yesterday. The show will be aired in the US today.

Her girlfriend, actress Portia De Rossi, was in the studio when Ellen made the announcement and they were applauded by audience members.

Ellen has been an outspoken advocate of gay and lesbian rights since she appeared on the cover of Time magazine 11 years ago under the headline, “Yep, I’m Gay.”

A massive sitcom star across the world, she lobbied ABC to allow her onscreen character, Ellen Morgan came out as well during the April 30th 1997, episode of Ellen.

“Ellen coming out ten years ago kicked off a tremendous decade of visibility for lesbian, gay, bisexual and transgender people,” says GLAAD President Neil G. Giuliano.

“Ellen opened the closet door for shows like Will and Grace, The L Word and Ugly Betty to succeed, and for other out performers to live their lives openly and honestly. We know that with this kind of visibility comes understanding and acceptance.”

42 million people tuned in to the coming out show, The Puppy Episode, making it ABC’s most-watched programme of the season.

The episode went on to win an Emmy for Outstanding Writing and a Peabody Award.

In 2007 Ellen became the first out entertainer to present the Oscars ceremony.

Her daily chat show has attracted big-name stars as well as Presidential candidates.