The Oscar-winning actor was on location in the Rocky Mountains near Calgary to make Bookworm. In the film he plays a voracious reader married to Elle Macpherson who becomes an all-action hero.
Sir Anthony, 58, had been in the water for about 10 minutes shooting a sequence in which he survives a plane crash. He was taken from the remote area to hospital in Canmore, west of Calgary, suffering from suspected hypothermia and exhaustion.
A spokeswoman for the film said he was admitted to hospital on Monday "as a precaution". "Everything was fine, the water is extremely cold and he was dressed for it but we wanted to check everything was OK." She added the actor had quickly regained his strength and had returned to work. "He's fit as a fiddle. Quoting Shakespeare, as a matter of fact."
Crew members say the actor felt ill soon after emerging from the water. One said: "Tony felt disorientated, weak and faint. He was having difficulty speaking."
The actor's wife Jenni flew to Canada from her home in London to be with him but the spokeswoman said the trip had been planned before he was admitted to hospital.
Shortly before starting work on Bookworm, the Welsh-born star went on an intensive diet and lost two stone.
Last year Sir Anthony, who lives in California, suffered a trapped nerve between his shoulders. He recently told a magazine the incident had made him realise he had been pushing his health to the limit.
At the weekend it emerged that the actor's latest film, Surviving Picasso, in which Sir Anthony plays the artist, would not have its world premiere as expected at the Venice film festival which starts tomorrow.
The Merchant Ivory film was made amid fierce criticism from Picasso's son Claude and mistress of 15 years Franoise Gilot who have prevented any of his paintings from being featured.Reuse content