Tom and his crew hit the stage Thursday at Headliners Music Hall in Louisville, Kentucky for the latest stop of the "Tom Sandoval & The Most Extras" tour -- and one eyewitness told us he brought the house down ... with fans showing him a ton of love during his hour-long set.

Throughout the night, he played a number of '70s, '80s and '90s hits ... including "Somebody to Love" by Queen and "Groove Is in the Heart" by Deee-Lite, and the fans ate it up.

Sandoval busted out his go-to moves -- going shirtless and snapping photos with fans, and before the night ended ... he signed "Stay Fancy" in marker on a woman's arm.

Of course, all the love he's getting while performing is a huge contrast to the way things are going IRL.

As you know, the "Vanderpump Rules" star has been in very hot water ever since word got out he was cheating on his longtime partner Ariana Madix with their friend/costar Raquel Leviss.

Naturally, that put a hard stop on their 10-year relationship, and almost all of his cast members have been ripped left and right, in public and on the "Vanderpump Rules" reunion.

Despite all this, we were told he's still selling out shows. You'll recall, his security team kicked out one fan from his Pittsburgh show after she held up a #TeamAriana sign.