The Big Three is officially a memory because Ray Allen is headed to South Beach.

Late Friday night, Allen agreed to join the Miami Heat on a three-year contract, according to NBA sources. Heat owner Micky Arison let the NBA world know of the news through Twitter, making Allen's departure from the Celtics painfully official.

NBA players cannot officially sign new contracts until the moratorium ends July 11.

Allen will go to Miami for half the money the Celtics were offering, choosing the better weather, the chance to play with LeBron James and Dwyane Wade, and a fresh start with a new team.

Allen was unhappy during his final season in Boston, again placed on the trading block because of his expiring contract. He was forced to approach coach Doc Rivers about moving to the bench when second-year guard Avery Bradley began to blossom as a defensive force.