He's just defied his "chronic" jetlag to get up at 4am to appear on breakfast TV before completing a series of interviews, almost simultaneously chasing up matters back in the US.
Of course, talking about yourself and going on telly to promote your forthcoming tour isn't the hardest job, but Osmond wouldn't suggest it is.
"I'm enjoying myself, more and more. I like to work hard, and I get that from my dad. He was an army sergeant, tough and strict. He wasn't Joe Jackson, I don't want to paint that picture," he says, referring to the fearsome father of Michael and his siblings.
Seeing him now, with an award-winning Las Vegas show, it's odd to think he and Michael Jackson were once rivals. They were both the young focal point of their hugely successful family vocal groups before branching out on their own to become teen idols. But all didn't go well for Osmond after that.
"It's no secret that I lost my career in the 80s so I worked hard to get it back," he says.
"And second time around you know what it's like when things do slip away. I really don't want it to happen again. There are some big lessons, and that was a bad time of my life."
These were his wilderness years; too old to be a teen idol and unable to make the transition to grown-up pop star.
It wasn't until 1989's Soldier Of Love that things started to turn around, but that came after years of little attention and thoughts of packing it in.
What else he would have done, he's not sure, although with a love and great knowledge of IT, Osmond thinks it could have involved computers.
"Can you imagine the guy who sang Puppy Love coming to your house to fix your PC?" he says, laughing.
"To be honest, I don't know what I would've done. What's nice is that I had a lot of time to think about it all, and I really appreciate what I've got now.
"I was watching One Direction recently and I just hope they appreciate everything they have in their career. It's not going to last forever.
"I hope Justin Bieber is loving every moment of his career. That level can't be sustained.
"No matter how great your music is, the attention span of the public is that of a gnat, and it's getting shorter and shorter."
Despite this, Osmond has earned a degree of longevity.
Even if he and the rest of his family aren't surrounded by the same levels of hysteria they once were, the queue of autograph hunters waiting for him outside the TV studio we're sitting in is a reminder of his status.
There will also be new fans coming to the Osmond party thanks to his and sister Marie's Vegas show. They've been performing there five nights a week since June 2010 and are bringing the show to the UK.
"I love the UK and always have, but I haven't been able to get here as often as I'd have liked over the past few years," he says. "The Vegas show ties me down. But we get a lot of people from the UK coming to see us in Vegas, so it was only right that we brought it here. It'll be the same show, and much more.
"We play to a 750-seat room each night there, but we're doing arenas on this tour so everything will be bigger. We've beefed everything up."
BRITAIN'S Got Talent winner Susan Boyle will be joining him and his sister on stage for the London and Glasgow gigs.
Osmond first saw Boyle on Britain's Got Talent.
"Since we recorded together last year, my regard for her has only grown and I'm looking forward to performing with her in two cities that mean so much to both of us and our careers. The show is already jammed, and what could be a better addition than Susan Boyle?"
As well as duets in the show, Donny and Marie will sing their solo hits, including her Paper Roses and his Puppy Love.
"That song!" he says, smiling. "Once upon a time I would've said I'd sung it too many times. I hated it at one time. But now? I'd say I haven't sung it enough.
"There will be some Osmonds songs on this tour too – Love Me For A Reason, Crazy Horses and things – plus special stuff on big video screens behind us. I don't want to give too much away."
Between 1976 and 1979 Donny and Marie hosted their own variety show on US TV, simply called Donny And Marie. Before that The Osmonds had been one of the Seventies' most popular and busiest touring bands.
"I'll be walking down the street and someone will say 'Hi, where's Marie?' and I reply 'I don't know.' We're not in each other's pockets, she has her life in Vegas, I have mine in Utah and we only see each other on stage," he says.
"Don't get me wrong, we're close. We have our big family Christmases and Thanks-givings and so on, but we aren't all joined at the hip."
l Donny and Marie Osmond play the SECC on February 1