The Boston Celtics and Philadelphia 76ers have officially completed a blockbuster trade that sends the No. 1 overall pick in this week's NBA draft from Boston to Philadelphia.

The Sixers, who are expected to select Washington guard Markelle Fultz first overall, traded the No. 3 overall pick and a future first-round pick to the Celtics.

The future first-rounder sent to Boston will either be the Los Angeles Lakers' selection next year -- if it falls between Nos. 2 and 5 -- or a first-rounder in 2019, belonging either to Sacramento or Philadelphia. The teams announced the deal on Monday.

"We're thrilled to be able to select what we expect [to] be an impact player with the third pick in this year's very talented draft class, while also adding a highly valuable future asset as we continue to build toward Banner 18," Celtics president of basketball operations Danny Ainge said in a statement.

It will mark the second straight year that Philadelphia selects first overall. The Sixers used the No. 1 pick last year on Ben Simmons, who missed the entire season because of a foot injury.