John Stamos is celebrating his birthday with a steamy mirror selfie.The now 63-year-old "Full House" star took to Instagram to celebrate his birthday with a mirror selfie featuring him in his birthday suit, which he captioned, "63."Fans went wild in the comments section, with many making references to his character in the popular '90s sitcom, Uncle Jesse.While his phone blocked his face, the black-and-white photo showed off Stamos' toned abs and gave fans a peek at the tattoo on his left shoulder.Stamos shared a black and white mirror selfie of him in his birthday suit in celebration of his 63rd birthday.(Christopher Polk/Variety)SOFIA VERGARA SIZZLES IN RED BIKINI WHILE CELEBRATING 54TH BIRTHDAY ON YACHT IN ITALY"More like Uncle Yes-se! Happy Birthday!️" one fan wrote, while another added, "HAVE MERCY," which was his character's catchphrase in the show.Other comments included catchphrases from the show, with one writing, "You Still Got It Dude " and another adding, "️ it outttttt! "Another fan added, "Not John Stamos with the thirst trap ...