Harry Potter star Tom Felton was carried off a Wisconsin golf course after collapsing during a celebrity match ahead of the Ryder Cup.
The actor, who turned 34 on Wednesday, experienced a "medical incident" and was sent to a "local hospital for treatment", the PGA of America said.
Pictures showed him conscious while being removed in a cart.
Mr Felton is well known for playing Harry Potter's rival Draco Malfoy in the film franchise.
"In today's Ryder Cup Celebrity Match, actor and musician Tom Felton experienced a medical incident on the course while participating for Europe," the PGA of America said in a statement on Thursday.
"He was transported to a local hospital for treatment. No further details are available."
A keen golfer, Mr Felton was representing Europe alongside former professional ice hockey player Teemu Selanne, from Finland, in the celebrity tournament at Whistling Straits.
They were playing against 1980 US Olympic hockey captain Mike Eurzione and Olympic speed skater Dan Jansen.