Shaquille O'Neal Uses Shaggy, Doubles Down On Denial After Viral PDA Pic

Shaquille O'Neal still adamantly denies he's the big man in the photo burning up social media, using a Shaggy hit to get the word out ... this after the woman shared evidence she claims proves she was with the Big Fella!

52-year-old Shaq shared a video on Instagram ... where the Hall of Famer, sitting alongside Peter Gunz, lip-synced to Shaggy's 2000 hit, "It Wasn't Me".

The video is a response to a woman named Maria Ozuna Teachey ... who earlier in the week shared a now-deleted Rated-R photo with a giant dude who many assumed was O'Neal (the person is so tall their head is out of frame).

Shaquille headed for the comment section on Tuesday, plainly saying, "Nope not the kid," denying it was him in the photo.

But, Teachey wasn't willing to let it go, posting alleged receipts that aimed to show she was in O'Neal's room at Harrah's casino in Atlantic City, including a note from hotel staff.

"Shaquille, welcome back to Harrah's Atlantic City & The Pool. Looking forward to an awesome show!" the alleged note read.

For what it's worth, Shaq performed at a club in the casino on August 17 ... which doesn't mean it was O'Neal, but does seem to show he was in the area.

As for fans -- everyone's got a take, and some think Shaq's dogs are giving him away.

"Look at the jacked up feet, that’s him. He him fee fi fo fum big toe Shaq."