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.

Before joining Boston as the top assistant under Joe Mazzulla last summer, Lee spent five years under two-time NBA Coach of the Year Mike Budenholzer with the Bucks and was a part of Milwaukee’s 2021 NBA championship run.

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, where he had been the Patriot League Player of the Year in his senior season of 2006. After playing two years of international professional basketball, Lee joined Budenholzer’s staff with the Hawks in 2014 before moving to the Bucks in 2018 and the Celtics last summer.