Despite such names as Katie Couric and Bette Midler that were bandied about as replacements for Rosie O'Donnell once the talk-show host vacates her TV desk at the end of next season, the winner is . . . perky comic Caroline Rhea, 37, a frequent "Hollywood Square" and the daffy Aunt Hilda on "Sabrina, the Teenage Witch." "I'm thrilled to be working with Rosie," said Rhea, who filled in for O'Donnell, 39, as guest host of "The Rosie O'Donnell Show" several times last season. "As a kid, I always wanted to be Carol Burnett or Johnny Carson. I love to chat and entertain," she told the Hollywood Reporter. Rhea will assume O'Donnell's hosting duties full time with a newly named show for the 2002-03 season after O'Donnell steps down as planned, it was officially announced by Warner Bros. Domestic TV Distribution on Friday. (Warners TV, like PEOPLE, is part of AOL Time Warner.) In a statement about the former stand-up comic, O'Donnell, who reportedly plans to move to Florida and yet still run her New York-based magazine Rosie, said: "Caroline is very funny. She's self-deprecating, she's intelligent, she's smart, she's sensitive, and she cares about people in a way that's very relatable (sic) and accessible."