To celebrate Jennifer Aniston's 45th birthday, check out her hot recent bikini shots plus her workout and diet secrets Credit: FAMEFLYNET

So this is Jennifer Aniston's birthday suit -- at age 45!!

To celebrate our favorite "Friend" on her 45th birthday, Feb. 11, Us Weekly has rounded up a few of her best bikini shots from her recent December vacation to Cabo San Lucas, plus the superstar's workout and diet secrets to maintaining her enviable figure.

Aniston, toned and sexy in an itty bitty black bikini, and fiance Justin Theroux, 42, rented a home in face vacation spot Puerto Los Cabos, Mexico, so they and fellow A-list guests Courteney Cox, Howard Stern, Beth Ostrosky, Jimmy Kimmel, and Molly McNearney could relax and soak up the sun.

The We're the Millers star, here in a green bikini with Theroux, has credited yoga with keeping her insane body in shape since she began practicing with instructor Mandy Ingber. "My legs got leaner. My arms got strong," she has said. "I've maybe even grown half an inch from aligning my spine."

While the Friends alum is clearly not shy about showing off her body (Check out those toned abs in her purple bikini!), to prepare for her stripping scene in We're the Millers, Aniston kept a super-strict diet. "I was on a very like, you know, greens and vegetables and lean proteins and kale," Aniston said. "When I really wanted to have a cheat day, I had to have a kale chip."

Otherwise, the bride-to-be sticks to a clean diet. "I am always trying to eat organic and natural foods," she said. And when she indulged on a Big Mac while on a road trip with fiance Justin Theroux? "Wow, my body did not react well to that! It was like putting gasoline in a purified system."