If Elton John was going to show up in some form to support the premiere of his first toon, “Gnomeo and Juliet,” it was only fitting that he did so as the Piano Man. After the film’s screening inside Hollywood’s El Capitan Theater on Sunday afternoon, the screen raised to reveal John sitting at a bright red piano and got the crowd to join him in a rousing rendition of “Crocodile Rock.”

“I’m not biased,” he said, referring to the piano’s red shade, which represents one of the warring families of garden gnomes in the film (the other is blue). “I wanted a blue piano, too, but I couldn’t find one.”

John and partner David Furnish, the film’s co-producer, joined the dessert reception at the Highlands across the street where the guest list included Gavin Rossdale and David Copperfield, as well as the film’s voice actors Emily Blunt, James McAvoy, Matt Lucas, Patrick Stewart and Ashley Jensen. Sharon Osbourne and son Jack attended in place of Ozzy Osbourne, who voices a dim-witted deer in the film. “Gnomeo and Juliet” features classic and several new songs from John, including a duet with Lady Gaga.

Disney agreed to release the Miramax-produced pic after the Mouse House sold off the speciality label, which nearly left the toon without a distributor. After spending three years working on the film, Kelly Asbury, who co-directed DreamWorks Animation’s “Shrek 2,” was elated to finally see the garden-gnome romance make it to the bigscreen. “I feel like the groom at a wedding,” he said while mingling with guests. “This is like my bar mitzvah.”