The "SexyBack" singer brought Watt out during the second Houston show of his Man of the Woods tour at the Toyota Center Friday night.
The stars indulged in a shot on stage, Timberlake said " Cheers to a resilient city of Houston, Texas. May the Houston Rockets make the Finals."
J.T. also talked about Watt being such a great humanitarian, saying that the city of Houston is lucky to have him.
"I'm proud to say he's my friend. I'm proud to be here tonight with my bro," J.T. said in front of thousands of fans.
Fans first saw the two stars sitting courtside next to each other at the Toyota Center as the Houston Rockets pulled ahead of the Warriors in Game 5.
During J.T.'s final show in Houston, he paid tribute to the Santa Fe High School victims. Timberlake asked fans to turn on their cellphone lights and sing along to his hit single "Till the End of Time."