Olivia Wilde Flaunts Her Toned Glutes and Tattoo in Bday IG

• Olivia Wilde is turning 39 in style, and she shared an Instagram photo to commemorate the special occasion.

• The actress posted a pic posing next to her friend with her sculpted butt and legs on full display in a cheeky bikini.

• When it comes to her workouts, Olivia loves doing Tracy Anderson Method classes and spinning.

Happy Birthday, Olivia Wilde! The Don't Worry Darling actress and director celebrated her 39th birthday this year by rocking a bikini with a friend on Instagram. But of course, she did it in true Olivia fashion, with her toned booty and legs on full display. Also visible was her booty tattoo, which she dubbed a "tramp stamp."

"39 and feeling fine. Thanks for the birthday love. I milked it for way too long and it’s been great. Here’s to whatever’s next. Probably not another tramp stamp but who knows. #shameless #howdareshe #thehorror ♥️," she captioned the pic.

Of course, Olivia's birthday post got lots of love. Trainer Tracy Anderson commented, "I’d put a TA on that cute booty! 39 is such an awesome age!!! It’s going to be an epic year! 🎂🎉♥️♥️♥️♥️♥️," and actress Megalyn Echikunwoke wrote, "🙀🙀🙀🙀 The nerve!"

One of Olivia's favorite workouts is the dance and strength-based Tracy Anderson Method. She was spotted leaving the trainer's gym in Los Angeles earlier this month two days in a row, and was also seen there last year.

She also is a fan of spin classes, and she previously told Women’s Health, “I make fun of it, but it's amazing, because you have to push yourself through this resistance, which is so therapeutic."