A man named by British media outlets as European Ryder Cup player Thorbjorn Olesen was arrested at Heathrow Airport.
London police confirmed an arrest was made on Monday, without naming the man.
"Officers based at Heathrow Airport arrested a 29-year-old man on an in-bound flight on suspicion of sexual assault, being drunk on board an aircraft and failing to comply with the orders of cabin crew," police said in a statement to Reuters.
"He was taken into custody and subsequently released under investigation."
Olesen's agent Rory Flanagan did not respond to a request for comment.
Olesen, a Dane with five European Tour victories, played in a World Golf Championships event in Memphis last week, finishing equal 27th.
He made his Ryder Cup debut in Paris last year, beating American Jordan Spieth in the final-day singles.
Olesen was not scheduled to play this week.