Backstreet Boy A.J. McLean is back with a brand new thicker 'do!

On Saturday, the 35-year-old posted a picture on Instagram showing off his full head of hair.

The singer embraced his cosmetic surgery writing with the photo, "Some girls get there [sic] boobs done some guys get abb [sic] implants all to make them happy! This was the one thing I did and I couldn't be happier thank u dr G!!!!"

We think it's awesome that the former pop star was so candid with his fans ... we would've never known otherwise!

McLean's hair transplant does look pretty great, right? Sound off below and click "Launch Gallery" above to see more stars who've admitted to plastic surgery!