Brittany Kerr APOLOGIZES for Jason Aldean Hookup -- 'Lapse in Judgment'

Brittany Kerr has issued an apology for getting up close and personal with married country singer Jason Aldean ... chalking the whole thing up to a "lapse in judgment."

The former "American Idol" contestant says, "The actions I portrayed recently were not a representation of my true character, but a lapse in judgment on my part."

She adds, "I would like to sincerely apologize to everyone that has been affected by this, including my friends & family."

We broke the story ... Aldean put the moves on Kerr on the patio of a crowded bar on the Sunset Strip last week. Jason later issued an apology ... saying the whole thing was a drunken mistake.

Here's the question/inconsistency. Brittany told friends after we first posted the pics that she didn't know Jason was married. So, if she did know ... why does she now say she had a "lapse in judgment?" Just asking.