Mick Jagger, 75, is healing after a successful early-April surgery to replace a heart valve, multiple outlets reported.

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Now his younger brother, musician Chris Jagger, 71, is speaking out about how the Rolling Stones frontman's heart condition was diagnosed -- and how he's lucky to be alive.

According to Chris, 71, Mick's heart condition was previously undetected and was only recently caught by doctors. "It just showed up on a scan so it could happen to anybody, you know," Chris told the Mirror Group's Sunday People, adding that it was the same condition that killed The Clash musician Joe Strummer at 50.

"It happened to Joe. He came back from walking the dogs and his wife found him collapsed on the sofa. He had this valve problem," Chris told the British newspaper. "His father died from it. It was hereditary. With Mick it came on a checkup. That is why when you get to a certain age they want to check for this, check for that. You get to 70, you got to be careful, you know."

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Chris said he was grateful his brother -- who was treated at a New York City hospital -- has the means to pay for top medical care without waiting. "I've had a few health issues," Chris said. "At least [Mick] has not got to wait in line for the NHS." (The NHS is the National Health Service, Britain's government-funded medical and health care system that the vast majority of British residents rely on.)

Mick's surgery came in the wake of the Rolling Stones' announcement that they would have to postpone the April launch of the North American leg of their "No FIlter" tour as Mick faced an undisclosed medical issue.

Mick and his bandmates are expected to resume the tour later this year without any problems. Still, Chris told the Sunday People of his brother, "Maybe he will slow down. Touring is a pressure." Chris also confirmed that Mick was doing well. "Mick is doing OK. I spoke to him... he's good."

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On April 5, Mick's rep told the New York Post that the singer's health issues had successfully been addressed, though stopped short of confirming the specifics of his medical treatment. "Mick Jagger has successfully undergone treatment. He is doing very well and is expected to make a full recovery," the rep said.

Mick himself took to Twitter later that day to let fans know he was doing well post-op. "Thank you everyone for all your messages of support, I'm feeling much better now and on the mend - and also a huge thank you to all the hospital staff for doing a superb job," he wrote.

According to People magazine, doctors are being extra cautious with Mick's recovery time to ensure it's safe for him to hit the stage again. "If it was someone else, they'd need to recover for two weeks," a source told People, "but because Mick jumps around and the performances are strenuous, he needed to postpone the tour."