The 2016 NBA champion and Special Olympics International announced the news on Tuesday ... with Thompson saying he's "excited and honored" to partner with the sports organization that provides competitions for five million athletes (kids and adults) with disabilities.

"This is a great opportunity to support an amazing organization, but also use my platform and voice to help support athletes with intellectual disabilities," Thompson said.

"As a Global Ambassador, I will help inspire others to be more inclusive and take action to help change the stereotypes that exist for people with disabilities."

Thompson -- who is in his second stint with Cleveland -- will help promote the organization ... as well as work with local and global entities through activations by the Special Olympics.

In fact, the Cavs are hosting 40 athletes from Special Olympics France for a basketball clinic while they're in Paris for their game against the Brooklyn Nets on Thursday.

Thompson will join a list of several NBA/WNBA players who are also Global Ambassadors for the Special Olympics ... including Phoenix Suns star Devin Booker and Elena Delle Donne of the Washington Mystics.

"Special Olympics is honored to name Tristan Thompson as our newest Global Ambassador," CEO Mary Davis said. "Tristan demonstrates passion and dedication to creating a more inclusive world where exclusion has no place, and everybody belongs and is respected."

"We join Tristan in his commitment to elevating inclusion in communities around the world and look forward to working with him to positively change the lives of people with intellectual disabilities."

Of course, Thompson working with the Special Olympics hits close to home ... his younger brother, Amari, was born with disabilities.