Kelly Preston and John Travolta Kelly Preston and John Travolta

Kelly Preston feels "amazing" after losing 39 pounds, she tells People.

"I lost 39 pounds, have more energy than I had 20 years ago — and I feel amazing," Preston says. "I'm going to be turning 50 next year — holy sh--! Hey, 50 is the new 30."

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The actress had set out to lose her baby weight from her pregnancy with 1-year-old son Benjamin Travolta, but she has now dropped below her pre-pregnancy weight, thanks to pal Kirstie Alley

's Organic Liaison weight-loss program. (Alley lost 100 pounds herself during and after her Dancing with the Stars run this spring.)"When I got pregnant at 48, I didn't know if my body would bounce back," Preston says. "I was so excited when my best friend created [the program's organic supplement system] Rescue Me." According to the program's website, Rescue Me targets cravings and "boosts natural energy." Preston recently signed on as an Organic Liaison spokeswoman. "It's pretty much the most genius thing ever," she says.