Heidi Montag: Jennifer Aniston's New Co-star

Heidi Montag will shoot a cameo in the forthcoming film Just Go With It.

The 23-year-old Hills starlet will take part in the Adam Sandler, Brooklyn Decker and Jennifer Aniston film due out in 2011, according to Access Hollywood.

“I was just cast in my first feature film comedy! I start filming [M]onday!” Heidi tweeted Thursday afternoon. “This is one of the best days of my life!”

Earlier this week, Heidi announced that she would no longer be managed by husband Spencer Pratt and would rely on psychic Aiden Chase instead.

“Having an intuitive psychic leading my team gives me an edge no one else has,” Heidi shared.