The Transformers actress took the title after amassing the most votes in FHM's annual poll.
"I'm not comfortable with it at all. It annoys me," she is quoted as saying.
The 22-year-old, who recently shot her first leading role in horror movie Jennifer's Body, admitted that she found the film's sex scenes awkward.
She said: "I have a few love scenes. I eat and seduce everyone - boys and girls. There's a lot of kissing and craziness. It was awkward, it's always awkward and it's never fun."