Country music superstar Jason Aldean got up close and personal with a former "A.I" contestant ... right in the open at a very public bar on the Sunset Strip. There's just one problem ... he's married to another woman.

TMZ obtained photos of Jason and Season 11 "A.I" contender Brittany Kerr taken on the crowded bar patio area at The Den on Wednesday night -- frequented by locals and tourists always on the hunt for celebrities.

In the photos Aldean and Kerr get very flirty ... hugging, touching each other and at one point it appears Aldean goes in for a kiss.

Aldean --- who performed this weekend in So Cal -- eventually left the bar in a cab without Brittany.

Here's the rub, Aldean is married to his high school sweetheart, Jessica Ussery, who he tied the knot with back in 2001 and they have 2 kids together.

We reached out to Aldean for comment several times but have not heard back. No comment from Kerr either.

Country music superstar Jason Aldean says his very open public display of affection with a former "American Idol" contestant -- who is NOT his wife -- was a huge, drunken mistake.

Jason released a statement today, apologizing for his indiscretion, after TMZ posted pictures early this morning of the country singer and "A.I." castoff Brittany Kerr getting up close and personal -- hugging, touching, and flirting at a very popular, crowded bar on the Sunset Strip (above).

Jason -- who has been married since 2001 -- says, "The truth is that I screwed up. I had too much to drink, let the party get out of hand and acted inappropriately at a bar."

He says, "I ultimately ended up embarrassing my family and myself." And then adds, "I left alone and that's the end of the story."