The 24-year-old lifted his shirt after scoring his second goal in the Danes' 3-2 defeat by Portugal at Euro 2012, revealing underpants sponsored by Irish bookmaker Paddy Power.
Denmark's FA - who are sponsored by rival bookies Ladbrokes - have told their man he must not wear the offending item again, but the player still faces a UEFA charge after breaking the organisation's rules on advertising.
The player himself - who was on loan at Sunderland last season - claims that he had no idea he was doing anything untoward.
"It is just a pair of lucky boxer shorts that I used in the first game as well and have used before the tournament," he insisted. "I didn't know that I was breaking any rules but I am aware of that now."
Yet suggestions that the stunt was carefully planned were only boosted by the speed with which Paddy Power tweeted a picture of the striker showing his kecks, and repeating that "lucky pants" claim.
Bendtner's ambush marketing seems to be in direct contravention of UEFA rules which insist "all kit items worn during the final tournament must be free of any sponsor advertising".
Whether pants count as 'kit' is probably a grey area - though UEFA will be keen to close the door on such pranks to stop a rash of other players landing, er, bum deals.
The Danes' defeat after a late winner for the Portuguese left Group B on a knife edge, with all four teams still in with a chance of progressing going into the final group stage match.