Cops were called to Moore's home at 4:50 a.m, Sgt. Gary Montgomery of the LAPD tells ET. The fire department treated the man, who was found unresponsive, at the scene, where he was later pronounced dead.
Commander Andrew Smith said there is no homicide investigation, as there's no evidence of foul play. Rather, they believe this to be an unfortunate, tragic accident.
Moore nor her three daughters -- Rumer, 26, Scout, 23, and Tallulah, 21 -- were at the house when the incident occurred. According to police, Moore's assistant had thrown a small party for about six people, including the victim. The man reportedly did not know how to swim, and he had been left alone outside for a few minutes. When someone walked back outside, they found the victim at the bottom of the pool.
Earlier this year, Moore was the victim of a robbery. Find out more details about the clothing and jewelry stole from her storage unit in the video below: