The star, best known for playing Mikaela Banes in the Transformers movies, has a cameo turn as a prostitute in the new flick from Borat funnyman Sacha Baron Cohen.
She told the Sun: “When I first started acting I was always playing the b****y or mean girl, then I was playing these cool, robotic women.
“I was growing tired of playing those kinds of characters and reinforcing this stereotype of me and having to play up to that when I was doing interviews.
“Now I feel I can be myself again. It’s given me the chance to get away from that sexy, icy image that I’ve been stuck with.”
The 25-year-old added: “I think the public can relate to me more easily in these kinds of movies.”
Megan – who next stars in comedy This Is 40 alongside Jason Segel, Paul Rudd and Chris O’Dowd, said of co-star Sacha: “I had a wonderful time. Sacha is very smart and funny. We had a great time working together.”