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This photo provided by Sotheby's shows the piano used in the movie "Casablanca."

NEW YORK -- A piano used in the classic film "Casablanca" sold for just over $600,000 on Friday, falling far short of predictions that it could fetch $1 million or more.

The 58-key upright piano on which actor and singer Dooley Wilson performed "As Time Goes By," the signature song of the 1942 film's star-crossed lovers played by Humphrey Bogart and Ingrid Bergman, sold at Sotheby's for $602,500 including commission. 

The auction house had assigned the iconic prop a pre-sale estimate of $800,000 to $1.2 million, given some astonishing prices attained by movie memorabilia in recent years. 

In the film, the character Sam (Wilson) plays the signature song "As Time Goes By" during flashback scenes set in Paris, as well as in Bogart's club in Casablanca, where he and Bergman rekindle their romance. 

Bergman's memorable lines included the imploring: "Play it, Sam. Play 'As Time Goes By.' " 

Sotheby's had sold the piano, which was the one used during the Paris flashback scenes, to a Japanese collector in 1988, who paid $154,000, one of the highest prices ever paid for a movie prop at the time. 

The film, set in Morocco during World War II, won three Academy Awards including best picture, best writing and best director for Michael Curtiz. 

The auction house did not identify the buyer. 

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Round up the usual suspects, it's time to honor "Casablanca," the Humphrey Bogart-Ingrid Bergman classic that premiered 70 years ago, on Nov. 26, 1942. Are there many movies as beautiful, or as beautifully quotable?

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Humphrey Bogart and Ingrid Bergman in "Casablanca."

Usual suspects are rounded up. Beautiful friendships have begun. Songs are played again, by Sam (though the line, famously misquoted, is really just "Play it, Sam" -- no "again" mentioned.)

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In Rick's famed tear-jerker of a goodbye to Ilsa, he tells her that "we'll always have Paris," and then reminds her that "the problems of three little people don't amount to a hill of beans in this crazy world."

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When Captain Renault announces that he is "shocked, shocked to find that gambling is going on in here," a croupier smoothly hands him his own winnings. 

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Bogart and Bergman.

And when Nazi Maj. Heinrich Strasser sneers to Renault that Bogart's Rick is just another "blundering American," Renault points out, "We mustn't underestimate American blundering. I was with them when they blundered into Berlin in 1918."

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Everybody comes to Rick's.

And of course, in a line that's been mangled and parodied from here to Morocco and back, Rick says of Ilsa, "of all the gin joints, in all the towns, in all the world, she walks into mine."

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Bogart and Bergman.

Movies like "Casablanca" don't come around every day, or even every decade. That's why it's distressing for many movie fans to read in the Wall Street Journal that a sequel, "Return to Casablanca," was written in the 1980s and could still have new life. (A sequel about a son of Rick and Ilsa? Who himself would be almost 70 now? Hey, maybe Harrison Ford can play him.)

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Sam (Dooley Wilson) would rather not play it again.

Of that possibility, the best that can be said for many fans may be: They might make a sequel, but they can't make us watch it.

Happy anniversary, "Casablanca." Here's looking at you, kid.

What's your favorite line from "Casablanca"? Should a sequel be made? Tell us on Facebook.

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