6/5/2013 12:01 AM PDT

It's Elisabetta Canalis!!!

Yes! That taught tush is property of Elisabetta Canalis -- George Clooney's ex-girlfriend!

The 34-year-old Italian stunner rocked a teeny tiny bikini at an L.A. pool this past weekend ... proving that George's loss ... was truly Steve-O's gain!

Then again, Clooney's banging Stacy Keibler these days ... so he didn't exactly lose either.