Credit: James Devaney/

Working on the raunchy Judd Apatow comedy Wanderlust, actress Malin Ackerman was mightily impressed with costar Jen Aniston, she tells

Aniston, 41, is "amazing", Ackerman gushed to Us Tuesday at the People's Choice Awards 2011 nominee announcements in West Hollywood.

In the flick, Aniston is rumored to go topless. True? "There's a very big maybe, yes...One of the cast members is a nudist," Ackerman teased, adding, "I am not the nudist!"

Despite staying vague on the topless talk, Ackerman couldn't stop praising her famous colleague. "She is an incredible woman in every area of life," she said of Aniston. "She's just so giving and wonderful with both feet on the ground. Just lovely, really exceptional."

In Wanderlust, Ackerman plays a member of a "hippie" commune which Aniston and onscreen husband Paul Rudd mistake for a bed and breakfast.

One nutty sequence, she said, involves characters "tripping" on a "crazy peyote-like drug."

The cast really had fun off-set, too. "[It was] an amazing love fest," Ackerman noted of the production, which shot in rural Georgia. "We all really got along, and it was nice to be in such a small town and you end up having dinner together and hanging out. Lot of karaoke!"