Beyonce — SLAPPED ON THE ASS … By Fan in Denmark

Beyonce was too damn bootylicious for one fan in Denmark … who reached up onto the stage and slapped the singer right on her ass during her concert last night.

Mrs. Carter was performing “Irreplaceable” at the Forum in Copenhagen … when a dude with front row seats lunged on to the stage and delivered a full 5-fingered smack to Beyonce”s left butt cheek.

Beyonce was PISSSSSSED — she stopped dead in her tracks … stared at the guy and said, “I”m gonna have you escorted out of here.”

It”s unclear if she followed through on her threat.