Fergie: I'm Working Out Every Day for Wedding
01/01/2009 AT 02:30 PM EST
And it's been no easy task after being forced to gain weight for her role in the upcoming movie, Nine.
"It's hard, I've been working out every day," she said before her New Year's Eve concert in Las Vegas at The Venetian.
Her pre-wedding workout routine: "A lot of hiking and doing a bunch of sit-ups, working my butt off and just, you know, try to maintain and stay healthy."
The Dutchess showed off her body at the Vegas concert and later at Lavo where she celebrated 2009 with fiancé Josh Duhamel.
Before the clock struck midnight, Fergie was planning their New Year's Eve kiss, telling reporters, "Josh is definitely getting lipstick on his face and maybe his neck.
At 12, the couple was spotting locking lips in a deep kiss on the club's catwalk. Then, at their VIP table, they snuggled close to each other while sipping champagne and talking to friends before leaving at 1 a.m.
Coast to Coast: Stars Ring in 2009