Richardson won a Tony award in 1998 for Cabaret
Natasha Richardson, the actress wife of actor Liam Neeson, is believed to be critically ill after a skiing accident.
The 45-year-old suffered head injuries at the Canadian resort of Mont Tremblant on Monday.
Neeson flew to be by her side at a Montreal hospital. Reports suggest she has since been transferred to a hospital in the US.
Richardson fell on the training slopes but did not show signs of injury until an hour later.
Internet rumours of Richardson's death were untrue, said a family spokesperson.
The agent for actress Vanessa Redgrave, Richardson's mother, confirmed that Neeson had left the set of his latest film, Chloe, which is shooting in Toronto, to be with his wife.
Redgrave is looking after the couple's two sons in New York.
The couple married in 1994 after appearing in the film Nell.
A member of Richardson's family, who spoke to the BBC but has asked not to be named, said the whole family was "very distressed" by the incident.
The statement from the Mont Tremblant resort in Canada said the actress "fell in a beginners' trail while taking a ski lesson".
"She was accompanied by an experienced ski instructor who immediately called the ski patrol," it continued.
"She did not show any visible sign of injury but the ski patrol followed strict procedures and brought her back to the bottom of the slope and insisted she should see a doctor."
The actress was later taken to the nearby Centre Hospitalier Laurentien before being transferred to the larger Hopital du Sacre-Coeur.
A spokesperson for the hospital in Montreal could not confirm whether the actress was still there on Tuesday morning, but suggested her family might make a statement on Wednesday.
The Press Association, however, reported that the actress had been treated and left Canada on a plane for the US.
Part of the Redgrave acting dynasty, Richardson is the daughter of Vanessa Redgrave and director Tony Richardson, and the sister of Nip/Tuck star Joely Richardson.
She has starred in a number of Hollywood films and acted opposite an 11-year-old Lindsay Lohan in 1998's The Parent Trap.
But she is better known for her work on the stage, winning a Tony award in 1998 for her starring role in Sam Mendes' Broadway production of Cabaret.