And for any aspiring jazz performers: "You can't beat a Trumpet."
She also knows plenty about just what it takes to succeed in reality TV, having participated in The Real Gilligan's Island (she was Ginger!) and also America's Dancing With The Stars and the BBC's Strictly Come Dancing.
Our Rachel has already been a judge and a host on other illustrious shows like Are You Hot? and Britain's Make Me a Supermodel, so she comes armed with internationally tested diplomatic lines for letting terrible contestants down gently.
She's also proved, several times, that she has a sympathetic and wide-ranging musical ear.
She married Rod Stewart, after all; dated Rock of Ages-era muso Kip Winger, so she'll know a good guitar riff when she hears one; and she was hip enough to appear in the Fountains of Wayne music video for Stacy's Mom back in 2003.
So Rachel's got a pretty well-rounded background in the entertainment industry. Maybe even more of a well-rounded background than either Ali Campbell of UB40 or Jason Kerrison of Opshop.
Sure they've got music covered but what do they know about dancing or novelty dog performances?
They do both have transgenerational appeal though, and Mr Campbell undoubtedly has a lot of fans in our fair nation. He's also well qualified to judge folks making songs "their own", as he's made a pretty lucrative career out of it himself (Red Red Wine, I Got You Babe ... etc). Though if it's all reggae bands on finals night, questions will be asked.
With Jason Kerrison along to be the nice judge and keep the other two grounded, I think they'll do alright.
When you stack them up next to the jurists in the show's other franchises (Sharon Osbourne, David Hasselhoff, Piers Morgan and an array of other actors and media personalities, not forgetting Simon Cowell), it seems they've got that one unifying prerequisite quality: they're all a little bit mad (doesn't Kerrison still think the world is going to end in December?)
Or if they aren't now, they will will be after sifting through 5000 auditions ...
- TimeOut