Tatum cheers on Tkachuk after winning NBA title

What was Boston Celtics star Jayson Tatum up to right after winning the NBA championship on Monday? Giving Florida Panthers forward Matthew Tkachuk a motivational message on social media, of course.

“Tkachuk! Yo, get it done tomorrow,” Tatum said in a social media video posted by the NBA. “One kid from St. Louis won a championship today. Let’s make it two tomorrow.”

Tkachuk and Tatum were classmates at Chaminade College Preparatory School, an independent Catholic school for boys in grades 6-12, in St. Louis.

The two former prep school classmates have been following in each other’s footsteps this postseason, each star leading his respective team to the championship round. Throughout the playoffs, the St. Louis natives have been rooting each other on from afar.

During Stanley Cup Final Media Day, Tkachuk said he’s been watching and cheering on Tatum and the Celtics.

“I think it would be unreal for Chaminade and all of St. Louis if we can both win it,” Tkachuk said. “Yeah, I’m definitely cheering for him. Definitely."

Tatum has also said he’s been cheering on Tkachuk and the Panthers throughout the Stanley Cup Playoffs.

“I’m a big Matthew fan,” Tatum said at a press conference after Game 2 of the NBA Finals. “I’m extremely happy for him and his family and hopefully they win it all.”

Tatum secured his championship on Monday with the Celtics' 106-88 Game 5 win against the Dallas Mavericks, and Tkachuk will have the opportunity to earn his title in Game 5 of the Stanley Cup Final against the Edmonton Oilers on Tuesday at Amerant Bank Arena in Sunrise, Fla. (8 p.m. ET; ABC, ESPN+, SN, TVAS CBC).

NHL.com staff writer Tracey Myers contributed to this report