And so it goes, indeed.

Billy Joel will not be attending the Tribeca Festival opening night world premiere of his documentary “Billy Joel: And So It Goes” next Wednesday, The Post can exclusively reveal.

The Piano Man will be sitting out on his big night after revealing that he was diagnosed with a brain disorder called normal pressure hydrocephalus.

“Our hearts are with Billy Joel and his family following today’s announcement,” Tribeca Festival co-founders Jane Rosenthal and Robert De Niro said in a statement. “As a New York icon and global music legend, he has profoundly shaped the cultural fabric of this city and touched audiences around the world. We send our love and full support and wish him strength and a healthy recovery.

“We’re deeply honored that this year’s Opening Night celebrates his remarkable legacy and enduring influence on New York’s cultural landscape,” the statement continued. “This is the perfect moment to recognize a creative force whose work reflects the very soul of our city — and the heart of Tribeca.”

Directed by Susan Lacy and Jessica Levin, “And So It Goes” features rare, previously unseen footage and candid, intimate interviews while charting the five-time Grammy winner’s rise from Long Island to international pop stardom. The documentary will be coming to HBO and HBO Max later this summer.

Normal pressure hydrocephalus is a brain disorder where cerebrospinal fluid builds up inside the skull and presses on the brain, disrupting cognitive functioning.

Due to his condition, the 76-year-old music legend also canceled all of his upcoming tour dates, which were to include a “Triple Play” summer series of concerts at all three New York area stadiums: Yankee Stadium (July 18, with Rod Stewart), MetLife Stadium (Aug. 8, with Stevie Nicks) and CitiField (Aug. 21, with Sting).

A statement posted on Joel’s Instagram last week explained that his condition worsened due to recent concerts, causing “problems with hearing, vision and balance.” The singer took a nasty fall during his concert at Mohegan Sun in Montville, Connecticut, in February.

“Under his doctor’s instructions, Billy is undergoing specific physical therapy and has been advised to refrain from performing during his recovery period,” the statement read. “Billy is thankful for the excellent care he is receiving and is fully committed to prioritizing his health. He is grateful for the support from fans during this time and looks forward to the day when he can once again take the stage.”

Joel added in his own statement: “I’m sincerely sorry to disappoint our audience, and thank you for understanding.”

But the good news is that, despite his diagnosis, Joel apparently isn’t ready to retire 10 months after moving out of Madison Square Garden, where his historic monthly residency ended last July after 10 years, 104 sold-out shows and 1.9 million tickets scanned.

“He is happiest while performing,” a music industry insider told People Tuesday. “Music is, has been and will always be his life. He’s not ready to retire.”

On Monday, the Rock & Roll Hall of Famer’s wife, Alexis Roderick Joel addressed fans on her husband’s Instagram.

“Thank you for the outpouring of love and support,” wrote Joel’s wife of 10 years, with whom he has daughters Della, 9, and Remy, 7. “We are so grateful for the wonderful care and swift diagnosis we received.”

Joel’s ex-wife and “Uptown Girl” muse, Christie Brinkley, and their daughter, Alexa Ray Joel, have also been showing big love to the “Big Shot.”

“Dear Billy, The whole Brinkley gang is sending you lots of love and good wishes for a full and speedy recovery,” Brinkley, 71, wrote on Instagram Saturday. “I was looking for some cute photos of you and Alexa to send you, when I came across this clip from a recent concert. It made me laugh … but it also reminded me of all the joy you create, and all the sensational singalongs you’ve led.”

Alexa, 39, for her part, shared: “We love you and we got you, Pop! I just wanted to thank you all for the beautiful outpouring of love and support amid the recent news of My Father’s health diagnosis. My Dad is the strongest and most resilient man I’ve ever known … and he’s entirely committed to making a full recovery with ongoing physical-therapy treatments as he continues to regain his strength.”