Los Angeles Police confirmed the man filed a complaint against Combs, who uses the stage name Diddy, E! News reported Wednesday.
"Officers took a report and the investigation is ongoing," an LAPD
TMZ.com identified the alleged victim as Gerard Rechnitzer.
The alleged incident occurred about 2:30 a.m. Monday at the Roosevelt Hotel, across the street from the Kodak Theater where the Academy Awards were presented hours before.
Combs allegedly invited Rechnitzer's fiancee to a party and then struck Rechnitzer when he tried to extricate his bride-to-be from the party, TMZ.com reported. Combs left before police arrived.
Rechnitzer was not seriously injured and refused medical treatment.
Combs' legal woes extended across the Atlantic. He lost a dispute over the use of his "Diddy" nickname in Britain.
London's High Court ruled Wednesday that Combs broke an agreement with record producer Richard "Diddy" Dearlove, who sued the entertainer last July for using the moniker "Diddy" in the cut "The Future" from Combs' latest release, "Press Play."
2014: The Year in Music [PHOTOS]