Michael Schumacher was reportedly admitted to a Paris hospital for a “secret treatment” late on Monday night.
The Formula 1 legend, who has not been seen in public in well over five years, turned 50 in January.
But since suffering traumatic head injuries, the German was placed in medical induced coma back in 2013, following a skiing accident.
The seven-time F1 world champion suffered the injuries in December 2013, and has been out of the public eye ever since, with scarce updates on his condition.
On Monday night, the news emerged that the 50-year-old had been taken to the Pompidou Hospital in southeast Paris.
French newspaper Le Parisian claimed that the F1 legend will receive a stem-cell transfusion.
He apparently arrived in the hospital on a stretcher with a blue cloth completely covering his body and face.
The treatment will reportedly begin early on Tuesday morning, with Schumacher scheduled to return home to Switzerland on Wednesday.
Schumacher’s condition is still largely unknown, due to the level of secrecy placed upon him and his inner circle at the request of his wife, Corinna.
The German still lives in Switzerland, and apparently watches F1 races on television, according to FIA president Jean Todt.
Earlier this year, Todt confirmed that he had travelled to Schumacher’s house in Lake Geneva to visit him.
“I’m always careful with such statements, but it’s true,” he told Radio Monte-Carlo.
“I saw the race together with Michael Schumacher at his home in Switzerland.
“Michael is in the best hands and is well looked after in his house.
“He does not give up and keeps fighting.”