That's one way to put rumors to rest.

On May 24, Teen Mom 2 star Jenelle Evans, 20, shared a racy bikini picture via Twitter, proudly showing off her new boob job -- all while slamming reports she's been knocked up by on-again love Gary Head. "No, I'm not pregnant. No, I'm not fat," she wrote. "Check out my new bathing suit. I love it. So bright!"

"I gained weight from my surgery and now all that extra weight is gone," Evans continued. "I have birth control in my arm -- it's called Implanon."

The MTV star added: "Maybe if I stop eating for a week my fiance would love me and I wouldn't be so [fat]. Tabloids can stop saying I'm pregnant."

Earlier this month, Us Weekly confirmed that Evans had accepted a proposal from Head, 22. "Gary asked her to marry him last month," a source said. "She wasn't certain about Gary and didn't want things to be that serious between them."

Head supported Evans as she recovered from her boob job, in which she went from a B to a "full C."

"Gary took care of her when she was recovering, and that made it solid to her, that he was really there for her," the source told Us.