"They asked me last week," Allen said before the Celtics-Dallas game. "I told them already that I would do it last week."
No announcement has been made about the competitors in the 3-point contest. Other Celtics were unaware of Allen's impending participation.
"You didn't tell me you were in it," Rajon Rondo said while Allen was being interviewed in the Celtics' lockerroom.
Asked about competing against teammate Paul Pierce, Allen replied: "I'm up for the challenge, I'm up for any challenge, I'm always up for a challenge. When would you ever think I would back down from shooting?"