"I've celebrated the accomplishments and witnessed the challenges my sister has experienced as a person with intellectual disabilities," Booker said Thursday.

"She motivates me every day, and I'm humbled to be part of Special Olympics, a global organization with a mission to help spread awareness about the abilities of people with intellectual disabilities."

Booker's 18-year-old sister was diagnosed with DiGeorge syndrome -- a rare genetic chromosomal disorder that can lead to mild intellectual disabilities.

23-year-old Booker says he's been so inspired by what she's been able to accomplish in the face of the adversity ... he's deeply involved himself in the Special Olympics.

Booker has invited special needs fans to NBA events constantly and has even donated annually to Special Olympics Arizona as part of his "Devin Booker Starting 5" charity efforts.

"People like Devin who have a sibling with intellectual disabilities possess inherent empathy for the population we serve," Special Olympics CEO Mary Davis says.

"We are lucky to leverage his passion to inspire others around the world to join our all-out effort to end discrimination against and empower people with intellectual disabilities.”