US President teases UFO Enthusiast Shirley MacLaine

Barack Obama has joked he may have been the first US president to mention Area 51 in public, at a White House honours event attended by UFO fanatic Shirley MacLaine.

"Now, when you first become president, one of the questions that people ask you is 'what's really going on in Area 51?'," he said.

"When I wanted to know, I'd call Shirley MacLaine. I think I just became the first president to ever publicly mention Area 51. How's that, Shirley?"

The actress was honoured at the prestigious Kennedy Center Honours event for her contribution to the arts along with artists including jazz pianist Herbie Hancock and musician Billy Joel.

Area 51 was the name given to a piece of land in the Nevada desert that became a focus for conspiracy theorists who believed it was a government base for captured UFOs.

The acknowledgement came in a US government history of the U-2 spy plane programme, obtained by George Washington University's National Security Archive through a public records request.

A British online survey in 2008 revealed that 61% of 1,000 people questioned believed in the existence of aliens.