Start Me Up: the Stones set to launch tour after Jagger surgery

The Rolling Stones were gearing up for the Chicago launch of their postponed North American tour on Friday, just months after legendary frontman Mick Jagger underwent heart surgery.

The ever-slim Jagger, sporting a black hoodie and baseball cap over his lush mane, posted a clip of himself strumming a guitar during rehearsals in the Midwestern city.

"Good morning Chicago! We can't wait to see you at Soldier Field later today," the iconic British band posted on social media.

Fan fears flared in April when the Stones, which formed in 1962, announced the postponement of a string of tour dates so the flamboyant Jagger, 75, could receive medical treatment.

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Shortly thereafter, doctors performed a minimally invasive transcatheter aortic valve replacement, allowing the artist to avoid a major operation that would require surgeons to open his chest.

"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," Jagger tweeted at the time.

The energetic artist known for his hard-partying youth has eight children, five grandchildren and a great-granddaughter, but has maintained a busy schedule of animated stage performances for decades.

The Stones' current tour, first scheduled for April to June, will see the rockers play 17 concerts in 15 arenas across North America, culminating in Miami on August 31.

The group will play Chicago's Soldier Field again on June 25 before heading to Ontario, Canada for a June 29 show north of Toronto.

Friday's concert will open with the American eight-piece soul group St. Paul & The Broken Bones.