"The Biggest Loser" is all about shedding pounds, but this season, host Alison Sweeney will be gaining -- and she broke the news while filming a session for the upcoming season of the series, "The Biggest Loser: Families."

ET has a first look at the emotional moment when a tearful Ali, who also stars as Sami Brady on "Days of our Lives," told the trainers and contestants, "I'm going to have a baby."

She got a big hug from trainers Bob Harper and Jillian Michaels, and Jillian joked, "Maybe this one will like me better than Bob."

Jillian, of course, was referring to Ali's three-year-old son, Ben, with husband, Dave Sanov.

The new season of "The Biggest Loser" will air this fall on NBC.