Lana Del Rey Claims She Kissed Morgan Wallen in New Song, Throws Shade

Lana Del Rey is kissing and telling ... the singer claimed she smooched Morgan Wallen -- and then threw shade at him -- in her brand new song "57.5", which she debuted at Stagecoach Friday night.

There's no guessing when it comes to the new song's lyrics as she sang ... "I kissed Morgan Wallen / I guess kissing me kind of went to his head / If you want my secret to success / I suggest don’t go ATVing with him when you’re out west."

Thanks for the advice.

Lana sang the head-turning confession on the Palomino stage after she announced to the energetic crowd that it would be "the last time" she was "ever going to say this line." She also debuted another new track, called "Husband of Mine."

It's unclear if the "Summertime Sadness" hitmaker actually swapped spit with the country crooner ... but we sure know who "Husband of Mine" is about -- her hubby Jeremy Dufrene. The pair tied the knot in a surprise ceremony back in September after meeting years earlier on one of his wildlife boat tours.

We reached out to Morgan's reps for comment on Lana's lyrics ... so far, no word back.

The "Whiskey Glasses" singer made headlines just a month ago after he was trolled for seemingly walking off the stage early at the end of the show after appearing as the musical guest for "Saturday Night Live."

Our 'SNL' sources said Morgan did nothing wrong ... though the show mocked the hooplah it caused the following week.