As Japan's new prime minister, Yukio Hatoyama, agonises over the formation of his government, he is unlikely to be losing much sleep dreaming up a role for his first lady. While Michelle Obama, Carla Bruni and Sarah Brown have all had to strike an awkward balance between supportive wife and public figure, Miyuki Hatoyama has cultivated a third role – that of pedlar of new age bunkum.

With the dust barely settled on last Sunday's election, Miyuki – whose husband will officially become Japan's leader on 16 September – is already emerging as a gloriously eccentric foil to her humdrum hubby. While he reassures the US that his country is committed to the bilateral alliance, she regales the media with tales of interplanetary travel and, er, solar breakfasts.

"I eat the sun," Miyuki says, raising her arms as if to tear pieces off an imaginary sun. "Like this: yum, yum, yum. It gives me enormous energy. My husband has recently started doing that too." Clearly, this is where Gordon Brown has been going wrong.

When she isn't tucking into the centrepiece of our solar system, the 66-year-old former dancer pens cookbooks with humble titles such as Hatoyama Miyuki's Hawaiian Spiritual Food. She makes her own clothes (including a skirt made from hemp coffee bags) and, as she demonstrated during the election campaign, can also do a very passable Moonwalk.

But it is her extraterrestrial experiences that have triggered an avalanche of media coverage her husband could never hope to match. In a book entitled Very Strange Things I've Encountered, his wife has claimed that she was abducted by aliens as she slept one night 20 years ago, then whisked off to the final frontier. "While my body was asleep, I think my soul rode on a triangular-shaped UFO and went to Venus," she wrote, adding: "It was a very beautiful place, and it was very green."

By happy coincidence, Miyuki is married to a man whom his parliamentary colleagues once nicknamed "the Alien", a comment on his sometimes otherworldly manner and an unkind reference to his prominent eyes. His wife's revelatory book was published last year, but only now have her foibles become staples of daytime television. Perhaps revealingly, she says that when she recounted her Venusian encounter to her first husband, he suggested it had probably been a dream. But her second, the 62-year-old Hatoyama, is more accommodating: "He has a different way of thinking and would surely say, 'Oh, that's great.'"

Michelle Obama, too, will surely be delighted to learn that Miyuki sees in her a kindred spirit. "I think she is so natural and has a kind of sensibility similar to mine. If I get the chance to meet her, I'd look forward to it."

Hatoyama appears admirably unruffled by his wife's idiosyncrasies, saying: "I feel relieved when I get home. She is like an energy-refuelling base." Miyuki, too, paints an idyllic picture of life chez Hatoyama, where her husband indulges his love of animal movies and feeds his addiction to prawn crackers.

She honed her theatrical delivery back in the 60s when performing for the Takarazuka Revue, an all-female theatrical troupe that specialises in kitsch adaptations of classics such as Guys and Dolls and The Sound of Music. After six years on the stage, she moved to the US with her Japanese restaurateur husband. It was there that she met Hatoyama, then a graduate student of engineering at Stanford University. They married in 1975.

The popular notion that Japanese women are demure and subservient is a lazy stereotype, but Miyuki's behaviour would seem bizarre in any country. Judged by the standards set by previous Japanese first ladies, it borders on the impertinent. In a TV interview earlier this year,she claimed she had met Tom Cruise in a previous life, in what must have been an unnerving meeting of Scientology and new age spiritualism.

"I have a dream that I still believe will come true, which is to make a film in Hollywood," she said. "The lead actor is Tom Cruise, of course. Why? Because he was Japanese in a previous life."

Cruise, whose closest professional brush with Japanese culture was a leading role in the ludicrous 2003 film Last Samurai, "would recognise me when I see him and say: 'Long time, no see!'" Michelle Obama may not be quite so effusive.

Stealing the show

Tim Dowling rates world leaders' partners for their 'colourful' personality traits.

Joachim Sauer

Married to Angela Merkel

Wacky rating 0.1 out of 5

Quiet and reserved, Sauer rarely appears in public and didn't even attend his wife's 2005 inauguration. Holds certain views about the nature of the universe that most ordinary people would find incomprehensible, in keeping with his job as a quantum chemist. No pictures of him with Tom Cruise.

Sarah Brown

Married to Gordon Brown

Wacky rating 1 out of 5

The very picture of common sense, British reserve and tireless discretion. May have married the only person in the world in contrast to whom she could be described as devil-may-care. And she picks out his ties for him.

Michelle Obama

Married to Barack Obama

Wacky rating 1.5 out of 5

Consistently down-to-earth, even when interviewed by Oprah. No known new age proclivities. Like Miyuki Hatoyama, claims to have met Tom Cruise - but photographic evidence would appear to support this. Did not say if she thought he was weird.

Carla Bruni

Married to Nicolas Sarkozy

Wacky rating 3 out of 5

Formerly given to pronouncements about being "bored by monogamy", and claimed her husband had "five or six brains which are remarkably irrigated", though she may not have meant it literally. The only G20 spouse (so far) to have nude photos and sex tapes stolen. Author of some decidedly flaky song lyrics ("I'm that time slipping by is a bastard making coats of our sorrow . . .")

Cherie Blair

Married to Tony Blair

Wacky rating 4 out of 5

The only G20 spouse, past or present, capable of giving Mrs Hatoyama a run for her mystical money. The crystal-pendant wearing, con-man consulting, magic-circle casting QC was said to have sought the help of the late Jack Templeton, a "homeopathic dowser healer" whose clients also numbered Jerry Hall and Princess Diana.

Miyuki Hatoyama

Married to Yukio Hatoyama

Wacky rating Off the scale

This professional "life composer" claims she once flew on a triangle-shaped UFO to Venus, and says she met Tom Cruise in a past life when he was Japanese. Makes her own clothes from hemp sacks and starts every morning by pretending to eat bits of the sun. "I get energy from it," she says, adding helpfully, "my husband also does this."