A piano used in the film Casablanca has been sold at auction in the United States for more than $US600,000.
The piano is associated with the song As Time Goes By and an on-screen romance between the film's two leads, Humphrey Bogart and Ingrid Bergman, when Bogart's character Rick utters the line: "Here's looking at you, kid."
It was sold to an unknown buyer at Sotheby's in New York on Friday by a collector in Japan to mark the film's 70th anniversary. The BBC reports the owner originally paid about $US154,000 for the piano at auction in the late 1980s.
The piano was used in the film by pianist Sam, played by Dooley Wilson, to play the song during a flashback scene set in a Paris bar.
The film, which is set in Morocco during World War II, won three Academy Awards including best picture, best writing and best director for Michael Curtiz.