We're told the ceremony took place at the Dwell Hotel in Chattanooga ... with the newlyweds wearing a lovely red and white ensemble that complemented one another.

But get this -- Diamond originally told McMahon they were going to a "red and white" Christmas party ... but to her surprise, she was actually getting all dressed up to attend her own wedding!!

As for why he chose Chattanooga, DDP says that he and Payge reunited there after 6 years on December 9th, 2019 ... and that his time spent with her is the most amazing relationship he's ever had.

But don't worry, it wasn't a complete shock -- Payge knew DDP was hoping to marry her before the end of the year ... and she began to put two and two together once she saw her family at the hotel.

There's more -- after they got hitched, DDP revealed a room full of a hundred of their friends so they could all celebrate together.

Listen to this list of guests -- former wrestler Rob Van Dam and his wife Katie Van Dam, Big Cass, and Enzo Amore came through for the special occasion ... and you know they couldn't let the night pass without throwing up DDP's signature hand sign.

The WWE Hall of Famer looked genuinely happy in the pics taken by Rachael Crowe ... and he said that his daughter, Brittany Page, helped him pull off the surprise.