(RollingStone.com) -- Elton John's fingers froze up midway through an outdoor performance following a screening of "The Union" last evening, the opening night of the Tribeca Film Festival. "Please excuse any wrong notes," he said to the crowd. "My hands are like ice!"
Along with such classics such as "Tiny Dancer," "Rocket Man," and "I Guess That's Why They Call It the Blues," John played two songs from "The Union" album -- "Gone to Shiloh" and "Never Too Old (To Hold Somebody)" -- for an audience that had just been schooled in how he wrote and recorded those songs with his longtime idol, Leon Russell.
Directed by Cameron Crowe and narrated by John, the documentary chronicles the making of the album, and was shot mostly during recording sessions with producer T-Bone Burnett in Los Angeles and at a subsequent concert in New York (look in the audience for a cameo by a comedian who might be the film's biggest fan).
"Whoopi Goldberg waved the flag for us," John told Rolling Stone. "She's the one who sent in the film [to the festival]. This was a project we were just filming because we wanted it for ourselves."
Originally, John wanted Crowe to join him in Africa on safari and shoot him writing a few songs. But while on that safari, John listened to some of Russell's older music, which inspired him to seek out and collaborate with the Seventies star. Once Russell agreed, John got Crowe to join him in Los Angeles instead to shoot in the studio, starting with the first day of writing.
In a phone interview, Crowe told Rolling Stone that the documentary started out as "just a hobby project, a labor of love. What was going to be one day of shooting turned into another day into another week into a year."
As the film progresses, Russell has to take a break from recording for emergency brain surgery, and comes back weakened. He slowly recovers, as John showers him with love and energy.
"When Elton John went to high-five Leon Russell -- and he said, 'I don't know how to do that. Is that a sports thing?' -- it doesn't get much better than that!" said director David O. Russell after the premiere. "That guy's the real deal."
Other musicians -- from Stevie Nicks in rare fangirl mode to a detached Brian Wilson -- come by to pay their respects to Russell and contribute to the sessions, with John happily taking a back seat.
The sudden onslaught of guests and admirers seems to rouse Russell, who then writes "In the Hands of Angels," a song about his recovery that moves John to tears. "That scene was beautiful," actor Paul Dano told Rolling Stone after the screening. "That was magic."
"As the story grew and Leon came out of his shell, I knew we had something special," John said. "And now he's a member of the Rock and Roll Hall of Fame, he's touring in Australia, and he's going to earn a million dollars."
Because of that Australia tour, though, Russell was not able to attend the premiere. Nor was Crowe, who's shooting a film called "We Bought A Zoo" in Los Angeles.
Both sent video greetings to the audience, however. Sporting a monkey on his shoulder, Crowe corralled his "Zoo" cast and crew, including Matt Damon, to take part in his.
Like many of the films at the festival, "The Union" is up for acquisition. "Everything up until now has just been about getting it ready to show, and anything beyond that, of a life beyond Tribeca, is a dream we can now realize," said Crowe. "Now that people have seen it, we're starting to figure it out."
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