Valerie Bertinelli Takes the Plunge!

Look out bikini babes -- Valerie Bertinelli is about to give you some serious competition at the beach!

The 48-year-old actress has dropped 50 pounds -- and is showing off her new body in a Jenny Craig ad, where she sports a teeny bikini! "I haven't worn one of these in 30 years," Bertinelli confesses in the ad. "This has done a lot to boost my confidence."

Val lost 40 pounds using the Jenny Craig system -- and revealed to Oprah how she dropped the other 10! "I get up and get on that treadmill I want to shoot!" Valerie confessed, "Lots of sit-ups, tricep dips -- anyone can do this at home. I do this at home!"

Bertinelli isn't the only celebrity waging a weight war -- former supermodel Kathy Ireland packed on 25 pounds before changing her lifestyle. The 46-year-old's son reportedly told her she looked pregnant, which motivated Kelly to beef up her workout routine, and trade sandwiches and fries for salads and surfing!

Kathy Griffin also busted her butt to get in shape! The funny gal, 48, worked hard to slim down -- and isn't afraid to admit it! "Just so you know, I've not had liposuction in 10 years," Kathy dishes. "I can't stand it when women say, "Oh, I never even notice what I eat, I forget to eat." I'm 48. I have to work out all the time."