Some Nobel laureates find out while on a plane, others think it's a hoax, and some don't even hear the phone ring.

On Tuesday, French physicist Serge Haroche was out walking with his wife when his cell phone rang. He saw the 46 country code on the display and recognised it immediately as a call from Sweden.

For a top scientist, a call from Sweden in early October can mean only one thing: a Nobel dream come true.

"I was in the street, passing near a bench, and was able to sit down immediately," he told journalists via a live link to Stockholm, describing the honour as "fairly overwhelming".

US researcher Robert Lefkowitz, who won the chemistry prize on Wednesday, admitted he had not heard the phone ringing when the all-important call came through.

"I was fast asleep and the phone rang. I did not hear it. I must share with you that I wear ear plugs to sleep, and so my wife gave me an elbow: 'phone for you.' And there it was. A total shock and surprise," he told reporters.

The prize-awarding academies make every effort to contact the winners about a half an hour before the official announcement is made.

The work honoured in the science fields -- medicine, physics and chemistry -- is often groundbreaking research done decades ago that has over the years led to advances in the respective areas.

As a result, the top scientists in their fields have an inkling their work may win, though the honours could come many years later.

After their revolutionary 1983 discovery that ulcers were mainly caused by a bacteria and not stress, Australia's Barry Marshall and Robin Warren began a tradition of meeting up at the pub on the day the Nobel Medicine prize was announced -- primarily to drown their sorrows over not winning.

But in 2005, the magical call did finally come.

"Once a year I'd round (Warren) up and we'd go and have fish and chips and a few beers," Marshall later said in an interview. "So we received a phone call on his cell phone about half an hour before the official announcement... was going to come out."

"I think you're just frozen -- it's the sort of thing that you can't really say that you felt a lot of emotion," he said.

The 1991 chemistry prize laureate, Richard Ernst of Switzerland, was on a plane when he got the news from Stockholm.

"The captain came to me and told me I had won the prize," Ernst said in an interview on the website.

"I went to the cockpit and spoke to Swiss radio and to my family," he said.

Louis Ignarro of the US, who won the 1998 medicine prize, was just about to board a plane at the airport in Nice, France, when a colleague known for pranks told him on a cell phone handed to him by an airport official that he had won the Nobel prize.

"Then I lost the connection. And I had to board the plane to Naples. So I never really knew if I had won it," he said.

"I thought that maybe if I had really won it, my picture would be in the papers, so I looked around. I thought maybe people would recognise my face. But no," he said.

When the plane landed, a professor from the university where he was going to hold a lecture met him on the tarmac with the printed announcement from the Nobel committee.

"It was in Swedish but I saw the word 'Nobel'," he said. "I actually dropped to the ground, I was so surprised and so jubilant."

Despite the committees' best efforts, there have been times they have failed to reach the winners.

The 2007 Nobel literature laureate Doris Lessing and the 1994 economics winner Reinhard Selten were both out food shopping when the prize was announced and only learned the news when they returned to their homes and were met by throngs of journalists.

Disbelief was the reaction Britain's James Mirrlees had to the phone call informing him he won the economics prize in 1996.

"I suggested possibly it wasn't true and needed some proof," he said, recalling he only believed it when a member of the Royal Swedish Academy of Sciences whom he knew personally came on the line and confirmed it.

And for the Austrian 2004 literature laureate Elfriede Jelinek, the call from Stockholm "felt like having a black hole in my head."