Los Angeles ? Stanley Donen says the idea was born when he encountered Arthur Freed on a street at the MGM studio in 1950.

Freed produced the studio’s “class” musicals. He also was a lyricist who had been at MGM since 1929’s “The Broadway Melody,” the first talkie to win an Academy Award as best picture.

As Donen recalls it, “Arthur said, ‘I’ve made movies with Rodgers and Hart, Berlin and Kern songs. Why don’t we do something with my songs?’

“‘Singin’ in the Rain’ was the result of that.”

“Singin’ in the Rain,” co-directed and co-choreographed by Donen and Gene Kelly and starring Kelly, Debbie Reynolds and Donald O’Connor, first reached America’s movie houses 50 years ago, on April 10, 1952. It was an immediate hit and has remained one of America’s best-loved musicals.

Critic Pauline Kael, often tough to impress, praised it years later in The New Yorker as “perhaps the most enjoyable of all movie musicals.” In 1998, the American Film Institute survey of the top 100 American movies ranked “Singin’ in the Rain” at No. 10.

And Kelly’s soggy solo in the title song has become one of the most replayed moments in film, right up there with Rhett’s emphatic goodbye to Scarlett in “Gone With the Wind” and Humphrey Bogart’s noble farewell to Ingrid Bergman in “Casablanca.”

To celebrate the film’s 50th anniversary, owner AOL Time Warner (the classic was part of the MGM library sold by the studio to Ted Turner) plans to release a newly restored 35mm print in selected theaters, and a DVD version with a new documentary in the fall.

PBS showed another new documentary, “Gene Kelly: Anatomy of a Dancer,” during a recent pledge break, and that, too, will be released as a DVD.

The right vehicle

Donen was recently asked if the filmmakers knew they were making a movie that would be revered a half-century later.

“You can’t get through a movie if you don’t think it’s good,” he replied. “Certainly we thought it was good. More than that? I don’t know. You don’t think about that. You just think about how you can do it. That’s what’s on your mind.”

Back in 1950, once MGM had green-lighted the “Singin’ in the Rain” project, Freed began looking for the right vehicle to feature the lyrics he had written for Nacio Herb Brown’s music. The producer hired Broadway aces Betty Comden and Adolph Green to write a screenplay.

Comden and Green had been fascinated with Hollywood’s transition to talkies in the late 1920s, when actors’ careers could be ruined by the sound of their voices. At first, they fashioned a story about a Western star who made a comeback in talkies as a singing cowboy. Howard Keel was considered for the role. But the cowboy was dumped for a song-and-dance man.

Kelly was the obvious choice as star, and he and his collaborator, Donen, enthusiastically joined the project. Freed wanted to cast Oscar Levant as Kelly’s on-screen collaborator, but Kelly, Donen and the writers insisted on a dancer. O’Connor, who had been dancing in B musicals and playing straight man to Francis the talking mule at Universal, was chosen.

Finding the female lead

For the leading lady, Freed took a chance on the 20-year-old Reynolds, who had played minor roles in two MGM musicals. She underwent punishing tap lessons to meet Kelly’s exacting standards. In the latter she failed.

“Gene was hard on me,” she said in an interview last year. “But he had to be. I had to learn everything in three to six months. Donald O’Connor had been dancing since he was 3 months old, Gene since he was 2 years old. Cyd Charisse and everybody were so talented. To be thrown in there, Gene knew I had to be challenged.

“I was terrified. I was crying. I was practicing and rehearsing all the time, my feet were bleeding. I was trying, but it was so much to learn.”

“Debbie was scared because she had never worked with two guys like Kelly and myself,” O’Connor said in a recent interview. “There was a lot of fear there. But Gene was just marvelous to her.”

“Debbie wasn’t a dancer; she hadn’t had the training,” Charisse explains. “I had just come out of a Russian Ballet company, so I was a very strong dancer. She did a helluva job, but I think she cried her way through it, because she was just sick. She wasn’t used to the drive that Gene had. He was very strong, and he liked to be the blue-collar guy, the man of the streets.”

Charisse was a latecomer to “Singin’ in the Rain.” Freed felt the movie needed a smash number for a finale, and he ordered a 15-minute ballet incorporating his songs “Broadway Melody” and “Broadway Rhythm.” Kelly’s assistant, Carol Haney, was cast as his dance partner, but Freed didn’t like her test and replaced her with Charisse, an MGM contract dancer.

Making a big splash

In a 1987 interview, Kelly who died in 1996 at age 83 recalled that one of the biggest challenges of his famous rain number was “how to get into it.”

He hated the Jeanette MacDonald-Nelson Eddy musicals in which the songbirds suddenly broke into a duet. “(Musical director) Roger Edens solved that by coming up with the ‘Doodedoo-doo”‘ intro, Kelly said.

In the movie, Kelly’s lovestruck character had just fallen for Reynolds’ chorus girl.

“This was my way of expressing it: by splashing around in the rain just like a kid,” Kelly remarked. “I remember when I was a boy in Pittsburgh. You couldn’t resist playing around in the slush, even though your mother told you not to.”

Always a meticulous planner, Kelly indicated where depressions should be dug in the studio street and sidewalk so he could splash them on cue with the music.

“We shot the number on a backlot street in the daytime,” Donen told The Associated Press. “Tarpaulins were pulled across overhead to make it night. It was summer when we were shooting, and under that tarpaulin it was extremely hot. Around 4 or 5 o’clock in the afternoon, we couldn’t shoot; people in Culver City were watering their lawns because of the heat and we lost our water pressure. But we got through it. You always find a way.”

The classic number was completed in a day and a half. And Kelly caught a cold.

Probably because the motion picture academy had bestowed seven Oscars and a special award on Kelly the previous year for another Freed-Kelly musical, “An American in Paris,” the academy voters overlooked “Singin’ in the Rain” among 1952’s movies.

It was nominated only for supporting actress (Jean Hagen) and for Lenny Hayton’s score, and won neither.