EXCLUSIVE

"iCarly" star Jennette McCurdy says she knows EXACTLY who leaked her racy selfies to the internet ... but the #1 suspect, NBA star Andre Drummond, tells TMZ Sports he's NOT the culprit.

The photos surfaced on several websites Monday ... and people immediately suspected the guy behind the leak was Drummond, since McCurdy humiliated him on a podcast over the weekend by spilling intimate details of their failed 1-week dating fling.

Moments ago, McCurdy even tweeted about the leak ... saying, "To anyone disappointed: I sent those pics to 1 person. You can connect the dots. Shocked someone would stoop so low. I just speak w/ candor."

We reached out to Drummond, who could not have been more adamant he's not to blame -- saying, "I did NOT leak any photos of JM."