"I'm celebrating my 21st year … and I decided that it's going to be my last year with the show," she says. "I have worked so much, and my daughter just turned 5 and my son is 9, and I just want to be with them."
No timetable has been set for Sami's exit, nor does Sweeney know what will happen to her character.
"It would be awesome to have some kind of happy ending," she says. "But then, I also think Sami probably deserves some sort of very twisted, like Breaking Bad ending."
Sweeney says she's never had more than a two-week vacation since joining DAYS in January 1993. She became the host of THE BIGGEST LOSER in 2007.
"For seven years I've done both shows," she says. "I'm really just excited to be with my kids and be with my husband and, I don't know, have fun. And I write. My second book's coming out. I love directing and just, you know, finding things to do."
Watch Sweeney make the announcement on ELLEN in the video clip below: