Boston Celtics lead assistant coach Charles Lee has agreed on a four-year contract to become the head coach of the Charlotte Hornets, sources told ESPN on Thursday morning.

Lee, 39, had risen to become one of the league’s most accomplished assistant coaches and now lands with new executive president of basketball operations Jeff Peterson in Charlotte to preside over the Hornets’ rebuild. Lee and Peterson began their NBA careers together with the Atlanta Hawks.

Lee will complete the Celtics’ playoff run before moving over to join the Hornets on a full-time basis, sources said.

Lee replaces Steve Clifford, who stepped down at the end of the season to move into a front office role. Charlotte has a chance to be much improved off a 21-61 season with the healthy return of All-Star point guard LaMelo Ball, the potential re-signing of free agent forward Miles Bridges and the rapid development of No. 2 overall pick Brandon Miller.

Lee started his coaching career in 2012 at Bucknell,