POSTED: Feb 12, 2015 1:07 AM ET
Warriors coach Steve Kerr, who will coach the team on Sunday in New York, made the announcement on Wednesday night.
Thompson is averaging 22.1 points and shooting 44 percent from 3-point range for the Warriors, who have the league's best record at 42-9. He will start alongside fellow Splash Brother Stephen Curry.
Harden is leading the league in scoring at 27.7 points per game.
The West also had one more open spot in the starting lineup after Pelicans forward Anthony Davis pulled out with a strained right shoulder.
Dallas Mavericks forward Dirk Nowitzki was named to replace him on the team and Kerr will set the starting lineup.
The 36-year-old Nowitzki is averaging 18.3 points and 5.9 rebounds per game. He went to 11 straight All-Star games before missing in 2013. He went again last year.