It is hard to reconcile the Seth MacFarlane who created the highly rated but often crude cartoon series Family Guy, American Dad! and The Cleveland Show with the Seth MacFarlane who’s a caramel-voiced, old-time singer who out-Bublés the crooner poster boy and will be singing at the Proms this week with the John Wilson Orchestra at London’s Royal Albert Hall.

And yet the 38-year-old four-time Emmy winner so gilded with talent and success that he’s reportedly paid $33 million a year - and has the replica Back to the Future DeLorean sports car to prove it - is the brains, voice and show-tune fanatic behind Music Is Better than Words, an album of covers from the dustier corners of the Great American Songbook.

“You think that money is everything and yet it’s anybody’s spring,” are the opening lines on the first song, It’s Anybody’s Spring, which might sound a bit rich coming from a rich guy whose Los Angeles home cost $13.5 million and whose production deal with the Fox television network is worth $100 million.

But MacFarlane insists there’s nothing arch, ironic or comedic about the album. He is entirely sincere. Such is his passion and enthusiasm for the project, you might think the Connecticut native a frustrated singer who would have had a career in music were it not for the pesky intrusion of a $2 billion TV franchise. But no.

“I’m somebody who would be pretty restless if I confined myself to one discipline,” he says, “no matter what it may be.”

Rock and pop held no interest for the teenage MacFarlane, who had his first newspaper comic strip published at the age of nine and who went on to study at the Rhode Island School of Design, where he developed the idea for Family Guy (he won a college animation prize, landed a job at Hanna-Barbera studios in LA and was swiftly on his way).

In the era of grunge and Britney Spears, the young fogey with the anarchic sense of humour viewed “normal” youth culture music as “kitsch and designed to be profitable in a particular era. It wasn’t really designed to endure in a way that the older songs were.”

So, in his 30s, with the world at his feet, MacFarlane was determined to re-create the songs in his head. He made Music Is Better than Words in the legendary Capitol Records recording studios in LA, using Frank Sinatra’s preferred microphone (borrowed from the Smithsonian) and working with a crack squad of orchestral players. His parents (father a teacher-turned-butcher, mother a school admissions officer) had raised MacFarlane and his sister on a diet of musicals, and he was determined to do justice to the music that always spoke loudest to him.

He’s long done it in his TV shows: a cornerstone of his vision for Family Guy when it started in 1999 was that the score and incidental music would always be fully orchestrated. “There’s a purity to the vocal style of that era that we were trying to shoot for,” says MacFarlane.

The immaculately groomed MacFarlane, then, is an old-fashioned guy, musically. But he’s a progressively minded - that is, gleefully offensive on occasion - scriptwriter and joke machine. Does that dichotomy sit easily within him?

“Yeah, but that’s something that I can’t take credit for myself. I view Monty Python as the great originator of that combination. The Meaning of Life in particular comes to mind, and my favourite example is Every Sperm Is Sacred.” MacFarlane is rhapsodically smitten by the troupe’s satirical song about the Catholic prohibition of contraception.

“It’s so beautifully written, it’s musically and lyrically legit, the orchestrations are fantastic, the choreography and the presentation are very, very complex – it’s treated seriously.

“It was clearly made by people who had a genuine love for show music. If there’s one cultural reference that I can point to that has been a total influence on what I do,” he declares, “it’s that piece in that movie.”

Of course, it’s easy to be controversial and anti-establishment if you’re making punk music. But if you can make those points within older, more traditional genres, that’s truly subversive.

“Absolutely. And in many ways it buys you a lot more leeway to be edgy. Family Guy is full of examples of content that would be very questionable to a lot of people, but is made palatable by the fact that it’s pleasant to the ear. The infamous Aids song is sung so well by this barbershop quartet… these four guys just sounded so tight that you can’t help but acknowledge that it’s pleasing to the ear despite the lyrics.”

MacFarlane’s Teflon-coated confidence also applies to Ted, his new buddy-movie about a walking, talking, swearing, cocaine-snorting teddy bear who blights the life of his “owner”, played by Mark Wahlberg. A huge box-office hit already in America, it is, it must be said, hilarious.

You won’t see many funnier scenes this year than the one in which a teddy bear - brilliantly realised by CGI - has a full-on, room-wrecking fight with beefy Mark Wahlberg.

But the 15-rated comedy has been criticised in some quarters for being vacuous. Does MacFarlane care? Does he hell.

“We never set out to make Schindler’s List,” is his party-line defence of his first feature. “The goal of this movie is to make people laugh as hard and as often as we can.”

Was Wahlberg right when he described the character of Ted - a foul-mouthed, sex-mad telly addict and camp-sci-fi-film fan - as “Seth on steroids”? MacFarlane chuckles about the bear he voices with a chewy Boston twang. “Ted is very different from me. It is a true characterisation.”

So, just to be clear: for all his serial bachelor status (he’s usually described as having dated a “string of starlets”), his riches, his encyclopedic passion and reverence for the world of Frank, Dean and Sammy, Seth MacFarlane is not a coke-taking Flash Gordon obsessive?

“I’m not. I barely even smoke pot more than once every six months.”

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For Seth's performance, watch BBC Proms 2012 - tonight at 8:00pm on Radio 3