The three times champion and former grand prix rider has been the series' dominant figure for the past three years. Yet until last week, the Scot's Yamaha team, whose sponsorship deal with Cadbury's Boost was wrapped up at the end of last season, were without the corporate backing required to mount another viable challenge.
Enter the publicity conscious tycoon and the offer of a financial lifeline that ensures Mackenzie and his No 1 plate will now appear in the 12-round campaign that opens at Brands Hatch on Sunday.
The veteran rider was beginning to wonder if he would be racing again when news of the deal reached him in Jerez, Spain, where the team - newly christened Team Virgin Yamaha - was testing its shiny new YZF-R7 machine.
"The team had been trying to find a sponsor but we still hadn't secured anything by last week," Mackenzie said yesterday. "I was really surprised that we'd gotten into that situation with our track record."
Understandably, Mackenzie is now a happy man - "relieved is an understatement" - after a few nervous months and an exercise in financial brinkmanship that has inevitably hampered preparations for the coming season.
"Our testing of the new bike has been limited because we didn't have a sponsor and it's been a mad rush to get the bike repainted and get a new set of leathers, but it's finally fallen into place," he added.
Never one to miss a PR opportunity, Branson issued an effusive statement yesterday to herald the deal. "We couldn't resist the temptation of supporting one of the finest riders in a generation," it read.
Mackenzie's talent is undisputed and acquiring the backing of the ambitious Branson - the thwarted global balloonist also owns a sizeable chunk of the London Broncos rugby league club - is a notable coup.
Mackenzie will need all the backing he can muster as this season he faces fierce competition from James Hayden's works-backed Suzuki and the Ducati- mounted Troy Baylis as well as the Kawasaki pairing of Chris Walker and Steve Hislop.Reuse content