The Beach Boys' Mike Love is "facing serious health challenges", according to John Stamos.

Ahead of their joint performance at the Ryman Auditorium in Nashville, Tennessee, on Sunday (11.l0.26), the 63-year-old actor took to Instagram to pay tribute to the 85-year-old founding member of the legendary rock band, who "insists on being on stage" despite his unknown health battle.

John shared two pictures of himself and Mike, with the caption: "I'm boarding a plane to Nashville to play with the Beach Boys at the Ryman Auditorium, struggling to put my feelings into words.

"My beloved friend, father figure, musical hero and mentor, Mike Love, is facing serious health challenges. We hope he'll be doing what he loves for years to come, but we don't know what the future holds. We have tonight.

"Mike is a fighter. Despite doctors, family and friends urging him to focus on his health, he insists on being on stage. He says he needs his band, the audience, his friends and drummer surrounding him to lift him up."

John, who has performed with The Beach Boys since 1985 and is a special guest on the band's tour to celebrate 60 years of their album, Pet Sounds, continued: "I've played with Mike for 41 years.

"I never imagined how deeply it would affect me to see someone larger than life face something so human and fragile.

"The Mike Love we see tonight may not be exactly the Mike we've always known. But he's still every bit the Mike we love."

The Full House star credited Mike's "lyrics, optimism, unforgettable hooks and more than 7,000 concerts" with bringing "joy to generations."

He went on to note Mike's "immeasurable" personal contributions to his life, including getting ordained to officiate the Born to Ride alum and 40-year-old actress Caitlin McHugh's wedding in 2018, as well as sharing experiences with the couple and their eight-year-old son, Billy.

John added: "Mike didn't just give me a place in his band. He gave me a place in his life.

"He taught me how to entertain, hold a stage, connect with an audience, and make people feel something. I carry those lessons everywhere. He's made me a better musician, entertainer and man.

"This life with Mike and the Beach Boys has become part of my identity. I've felt entrusted with being a steward of this extraordinary music, carrying it to new generations."

The ER entertainer said he wanted to be "completely present" at the Ryman Auditorium show, hearing "every harmony, familiar joke and cheer. Feel that first chord hit and watch age, illness and time disappear. Just a bunch of guys making music together".

John concluded: "Maybe the hardest part of loving someone is becoming so accustomed to the miracle of having them there that you forget it's a miracle at all.

"Tonight, I won't forget.

"I want to cherish every second without feeling those seconds slipping away.

"That's what I'm giving him.

"We don't know what tomorrow brings. But we have tonight."

Mike and fellow co-founder Al Jardine, 84, are the original founding members of The Beach Boys who are still alive.

Brothers Dennis, Carl, and Brian Wilson died in 1983, 1998, and 2025, respectively.