Atlanta Hawks guard Joe Johnson is the other competitor in TNT's special event, the network announced Tuesday. Johnson will play in the All-Star Game, while Durant and Mayo were selected for the rookie challenge.
The contest will take place outdoors at the NBA's All-Star Block Party on Saturday in Phoenix before TNT televises the All-Star Saturday night festivities.
If a player makes a shot in H-O-R-S-E, the next competitor must make the same shot or receive a letter. A player gets an 'H' for his first miss and is eliminated once he has all five letters of the word.
Players will have 24 seconds to execute their shots, and an NBA referee will rule if they're done properly. Dunking won't be allowed.