The actress will announce her big news during a guest spot on today's (Tuesday, January 21) episode of The Ellen DeGeneres Show.
"I've been on Days of Our Lives for 21 years. I celebrated my 21st year, this year. And I decided that it's going to be my last year with the show," said Sweeney, noting that she'd been appearing on Days and hosting The Biggest Loser for the last seven years.
Sweeney explained that she's been on the soap since she was 16 and has never had more than a two week vacation in that whole time.
"I mean, it's awesome," she added. "I love Sami. I love Salem. I love my job. I love daytime. I love the fans. I love everything about it, but I have worked so much. My daughter just turned 5 and my son is 9, and I just want to be with them and enjoy my last year. I'm going to be on Days all this year."
Sweeney had no last air date, nor does she know what will happen to her character.
"It would be awesome to have some sort of happy ending, but I also think that maybe Sami probably deserves to have some sort of very twisted Breaking Bad ending. She's caused a lot of people a lot of problems."
You can watch a clip of Sweeney's interview, here.
Photo Courtesy: NBC/Chris Haston