Despite gracing two Sports Illustrated covers and having a body to die for, Kate Upton said she was less than satisfied with her bikini scene in the new movie "The Other Woman."

The 21-year-old supermodel has received lots of buzz for the epic beach scene in "The Other Woman," which hit theaters on Friday, April 25. However, though Upton looks sizzling hot while running in a white bikini and has been compared to Bo Derek, according to Yahoo! News, she personally thinks that she didn't look her best.

"Of course, I always try to live a healthy lifestyle, but that was my birthday week," the blonde bombshell said to E! News. "So that was the least healthy I've ever been. I just turned 21." Upton will turn 22 on June 10.

She added that her co-stars, Cameron Diaz and Leslie Mann, helped her celebrate the milestone. "Cameron, Leslie and I were just living it up that week," she said.

Upton went on to described how comfortable Diaz and Mann made her feel when she first arrived on set.

"I was definitely nervous, and I didn't know what to expect," she said. "I'm the kind of person who really likes to know what's coming next, but Leslie and Cameron were just warm right away and supported me every step of the way and made me so comfortable. I felt like I was in a safe place.

"In comedy, it's important to feel like you're in a safe place so you could push your character and be silly and do ridiculous things," Upton continued.

She added, "The girls are so amazing. They're so funny and so talented and so fearless. I'm really lucky to have them as my partners."

Watch a clip from "The Other Woman" below.