Beyonce Blows Up Her Booty!

Secret butt-lift fixes post-baby curves — BOOBS ARE NEXT!

BEYONCÉ has put that sagging post-pregnancy butt behind her — and the tush tune-up went so well she's now looking at other body bits that moved south! 

Jay-Z’s been urging her to do this for years!” an insider tattled. “She finally warmed up to the idea.”

The mom of three, 35 — who had twins Rumi and Sir, siblings to 5-year-old Blue Ivy, on June 13 — once relied on exercise to keep her posterior perky. She claimed climbing stairs was “the best thing for butt cheeks!”