Valerie Bertinelli on the cover of People

Former One Day at a Timer Valerie Bertinelli is celebrating her upcoming 49th birthday by showing off her rocking bikini body.

Bertinelli, who has shed 50 pounds as a celebrity client and spokesperson for Jenny Craig, slipped into a string bikini for the cover of People's latest issue. Bertinelli said she hadn't worn a bikini since she was 20, but used her fear as motivation.

"I thought, am I really going to do this? Can I pull this off?" Bertinelli tells the magazine. Eventually, she loosened up. "Come on — it's just a bathing suit! I thought, if I'm so afraid of a bikini, there's something wrong. And so I had to get back into one!"

Bertinelli in her career has gone from America's Sweetheart to rock-star wife and back again. Last year, in the book Losing It: And Gaining My Life Back One Pound at a Time, she admitted that substance abuse and infidelity led to the end of her marriage with Eddie Van Halen. Now, however, Bertinelli says she's in the best shape of her life.

"I never, ever, ever had deltoids!" Bertinelli says. "When I'm doing exercises and I see them pop out, I'm like, Yes!"

What do you think of Bertinelli's new bod?