Elton John, who has been dealing with numerous health issues in recent years, is leaning on pal Joni Mitchell as a source of comfort and support.

"They're wobbly and can barely walk, but Elton admires Joni's bravery," an insider exclusively tells Closer. "If she can still sing and carry on with life, so can he. She has an indomitable, unbreakable spirit that Elton wishes he had."

Earlier this month, the legendary "Rocket Man" singer, 77, attended the New York Film Festival premiere of Elton John: Never Too Late with his husband, David Furnish.

After Elton sat in a chair on the red carpet to pose for photos with David, 62, and the documentary's codirector, R.J. Cutler, he spoke candidly about his recent health battles.

"To be honest with you, there's not much of me left. I don't have tonsils, adenoids or an appendix. I don't have a prostate," he admitted in a speech.

"I don't have a right hip or a left knee or a right knee. In fact, the only thing left to me is my left hip," Elton continued. "But I'm still here. And I can't thank you [enough], you're the people that made me."

Joni, who in 2015 suffered a near-fatal brain aneurysm that left her unable to sing, talk, play guitar or walk, has been Elton's "secret savior these past few months," says the Closer source, adding that he's taking "a lot of guidance from her."

Mike Inez, James Hetfield, Robert Trujillo, Billy Porter, David Furnish, Charlie Puth, Jacob Lusk, Joni Mitchell, Monique Ross, Carmen Carter, Brandi Carlile, Kenneth Ehrlich, Honorees Elton John and Bernie Taupin, Chauntee Ross, Adam Chester, Davey Johnstone, Georgey Taupin, Heather Taupin, Annie Lennox, Maren Morris, Nigel Olsson, Kirk Hammett, and Ken Stacey

According to the insider, "It's no secret he's been down on his luck and struck by one health issue after another, but he looks up to someone like Joni, and she's given him more will to live. He realizes there is a way back, and the best of what they've got has yet to come. Joni's positivity has been infectious."

During Joni's recent appearance at the Hollywood Bowl in Los Angeles, the singer, 80, was joined by Elton for her Joni Mitchell and the Joni Jam concert. The two shared the stage for a performance of the English singer's "I'm Still Standing."

Elton also shared backstage footage of an acoustic "I'm Still Standing," which he dubbed the "ultimate backstage Joni Jam."

Other special guests for the weekend of shows included Meryl Streep, Annie Lennox, Marcus Mumford, Brandi Carlile, Blake Mills, Jacob Collier, Robin Pecknold, Lucius, Allison Russell, Jon Batiste and more.

A separate source told Closer in September that these days, Elton can barely walk and has resorted to desperate measures to keep his condition hidden.

"Elton refuses to be seen as weak," said the insider. "He's so determined to maintain his larger-than-life image - but the truth is he can hardly move without help!"

During one particular red carpet appearance, he arrived in a custom purple golf cart - a move the insider claimed was to hide the pop icon's increasing reliance on a wheelchair.

Added the source, "Elton's focus now is all about cementing his legacy. He wants to control the narrative of his life as an artist, husband and father - before someone else does it for him!"