The singer has the ancient Egyptian symbol the Eye of Horus - also known as the Udjat which represents the Cosmos and is a symbol protection from evil forces - etched onto the back of his neck.

The symbol is also used by the U.S. research organization Enlightened Contact With Extraterrestrial Intelligence (ECTI), who Robbie recently spent time with tracking UFOs.

The pop heartthrob was at Trout Lake in Washington - where the group, set up by Ufologist James Gilliland, is based - trying to film any alien activity and also penned several new martian-inspired songs.

Alien expert Michael C. Luckman believes there are definite links between the Egyptians and intergalactic life-forms and says Robbie's choice of body art is a clear indication he is readying himself for a close encounter of the third kind.

Luckman, the director of the New York Center for Extraterrestrial Research, told BANG Showbiz: "By design, Robbie seems to be preparing himself, body, mind and soul, to take the ultimate journey to space in the very near future."

"I believe that Robbie is being drawn to James Gilliland's 70-acre ranch near Mount Adams, Washington, for what could well be the most significant event in human history - the joining of the civilizations. The place is known as America's number one UFO hotspot and is a magnet for true believers in aliens."

"When the time is right a number of special protocols will be set into motion to peacefully greet alien visitors to Earth."

Gilliland, who is becoming increasingly close to Robbie, claims he has already been visited by an alien, a "female humanoid being with feline features" which resembled "Sekhmet, a half-human, half-lion female god who is prominent in Egyptian mythology."

Robbie, 34, has become increasingly obsessed with extraterrestrials over the last few years and claims to have had three alien encounters, one of which happened as he was recording the song 'Arizona', which is about otherworldly contact.

He has also previously claimed he wants to quit music to devote more time to proving the existence of aliens.

Robbie said: "Seriously, I want to go out and investigate these things. I'm stopping being a pop star and I'm going to be a full-time Ufologist."