Lamar Odom is "doing great" after collapsing at his VIP booth at an L.A. nightclub

Lamar Odom collapsed while he was in a nightclub in Los Angeles on Sunday morning.

Per TMZ, Lamar's rep says he collapsed due to dehydration after an intense workout earlier in the day without the necessary fluids in his system. They also said it was very hot in the club, while adding ... he's "doing great."

Lamar Odom collapsed at his VIP booth at an L.A. nightclub early Sunday morning ... TMZ Sports has the video.  The person who shot the video tells TMZ Sports he saw Odom drinking for several hours before the incident.