BOOM. THERE IT IS -- Travis Kelce confirming he's back together with Kayla Nicole ... and just in time for the holidays!!

The Kansas City Chiefs tight end raved about Kayla during a Q&A sesh Monday with WNBA superstar Chiney Ogwumike -- confirming they've officially reconciled after taking a few months off.

Remember, Kelce and Kayla broke up suddenly back in August -- weeks after an awesome couples trip to Lake Tahoe with Patrick Mahomes and his fiancée Brittany Matthews.

Neither side explained the reasons for the split -- though Kelce had said rumors of infidelity were simply not true.

But, get this ... Kayla was recently spotted at a Chiefs game (hanging out with Matthews again) -- sparking hope she and Travis were back on good terms.

AND IT'S TRUE -- not only did they make up, they're dating again! Travis made the status of their relationship crystal clear during his convo with Ogwumike calling her his "girlfriend" and promising to shower her with gifts for the holidays.

"She's the best," Kelce said about Kayla ... "She's the absolute best."

Kelce and Kayla are definitely fan favorites when it comes to celebrity couples -- remember when they raged together during the Super Bowl parade in K.C. back in February???