A gorgeous hot blonde called Helen Clark

A stunning Prime Minister of New Zealand has made a surprise guest appearance on the David Letterman show in the United States - but it wasn't Helen Clark.

In a somewhat cryptic skit screened on Thursday night, Letterman made an announcement welcoming the Prime Minister on stage.

On cue, a tall blonde in a small pink dress walked on with a title on the screen identifying her as Helen Clark.

She clearly was not Helen Clark.

The woman waved, smiled, hugged Letterman and graciously accepted his praise for the "wonderful things" he had heard about New Zealand. She then exited to generous applause.

Just what prompted the unusual exchange is unclear, although it appears possible that the recent spate of publicity about personal attacks against politicians in New Zealand has travelled as far as the US.

Later in the show, which screens weeknights here on Prime, Letterman filled a regular slot known as the "Top Ten" with the "Top Ten Signs Your Husband Is Gay".

No link was made between the appearance of the woman and the "Top Ten", and there was a separate segment of about seven minutes between the items.

While the situation appeared a coincidence, it came on the day when Helen Clark's husband Peter Davis spoke about the recent rumours published about him.

Professor Davis said he felt he had been badly treated by the mainstream media following unsubstantiated rumours about his sexuality.

He said he tried to keep out of the spotlight, but as the Prime Minister's husband "you can't avoid it sometimes".

On Newstalk ZB he said he was not gay. "I'm certainly not that way inclined."

- Additional reporting NZPA