(CNN) Dripping with menace, the alien in Ridley Scott's 1979 space horror classic was quite literally the movie's break-out star.

With an extendible jaw that salivated acid, it wasn't enough that "Alien" could capture and kill; it wanted to use humans unfortunate enough to cross its path as a surrogate womb as well.

Yet while enthusiasts know much about the film's cast -- its heroine Ripley, played by Sigourney Weaver, and the unfortunate crew of the spaceship Nostromo -- the man behind the titular creature was nearly as elusive as his enduring on-screen character.

"Alien" was sold with the strap line "In space no one can hear you scream." Fittingly the actor in the suit, Bolaiji Badejo, was largely silent in his part in one of the 20th century's most celebrated films.

The six-foot-10-inch tall Nigerian is no longer with us, dying from sickle cell disease in 1992. But by talking to those who knew him on set we can piece together the story of one of Hollywood's greatest villains -- and one of its unlikeliest actors.

From squeezing into rubber suits to being covered in KY Jelly to mimic the appearance of acid, it was quite a way to earn your first film credit.

Close encounters of the thirst kind

Special effects supervisor Nick Allder laughs when recalling his first encounter with Badejo.

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"Ridley walked in with this guy. I thought I was looking at a giraffe... Stood in the doorway, you could see his body, but his head was above the frame."

Director Ridley Scott and associate producer Ivor Powell had long been scratching their heads as to who could fill the not inconsiderable shoes of Alien. Peter Mayhew (known for playing Chewbacca in "Star Wars") was considered, as were basketball players, mime artists and six-foot-three-inch" German model Veruschka von Lehndorff . But none were quite right for the otherworldly being created by Swiss surrealist artist, H.R. Giger.

"We'd had this vision of a praying mantis," Powell remembers. "We needed somebody incredibly tall with very long legs, so when they crouched down it gave the impression of an insect."

Eventually, Giger's creature emerged -- from a pub in Soho, London.

Born in Lagos, Nigeria, 1953, Bolaji Badejo was the son of the director general of the Nigerian Broadcasting Corporation and a welfare administrator, according to an interview his brother gave to the online blog Strange Shapes in 2014. He went on to study in Ethiopia and then the U.S., before moving to London to study graphic arts.

Casting agent Peter Ardram had been in a London pub when he saw Badejo, and called up Powell.

"'I've seen this guy in a bar,' he said. 'He's exactly what you were talking about. He's never acted before or done anything like that.'" A meeting was arranged.

"As soon as I walked in Ridley Scott knew he'd found the right person," Badejo said in a rare interview for the French film magazine, Cinefantastique, in 1979 (transcribed with permission by Strange Shapes ).

The Nigerian had long limbs and a slight figure, ideal for the role, but translating that into Giger's vision would be no mean feat.

Slipping into the part

Badejo had physical trainers build up muscles in certain areas of his body, remembers Allder, and took up mime classes, learning to move according to Scott's wishes.

"The idea," Badejo told Cinefantastique, "was that the creature was supposed to be graceful as well as vicious, requiring slow, deliberate movements."

This was made difficult by the lumbering presence of the alien's head, nearly a meter in length. In early test footage from inside "The Nostromo," Badejo can be seen skulking around the ship wearing a rudimentary alien head, becoming accustomed to the unavoidable sensory deprivation.

In the final outfit, designed by Giger and completed with the expertise of special-effects artist, Carlo Rambaldi, the actor could breathe and see a little, but not much else.

"I could barely see what was going on around me," Badejo recalled in 1979, "except when I was in a stationary position, while they were filming. Then there were a few holes I could look through... It was terribly hot... I could only have it on for about 15 or 20 minutes at a time. When I took it off, my head would be soaked."

Powell sympathized with the actor's predicament. "That dreaded suit must have been pretty uncomfortable and hard for him," he says. But the associate producer only knew the half of it. Allder says that at one point they'd planned to fill a cavity in the semi-transparent head with live maggots.

Alien, complete with protrusible jaw and acid saliva.

One quirk that did make it to the screen however was the alien's acidic saliva. In reality it was KY Jelly. And lots of it.

"We had to come up with a slime, something that didn't affect the suit," says Allder. "We tried wallpaper paste, all sorts, but KY Jelly just so happened to work.... We ended up phoning round every hospital and pharmacy open in the area, asking to buy as much they would let us have. We sounded like sex maniacs."

Standing seven-feet-tall in the suit, but walking around the six-foot-seven-inch high set, covered in lubricant and largely blind, playing the villain was not always a glamorous job. Yet "he never complained about it at," says Allder. "He really didn't."

"He did keep inside himself, quite a bit," the special effects supervisor remembers. "Being on a film set must have been quite strange for him. To have been the center of attraction... it was a bit of a shock to him."

Life after the final clapper

Bolaji with his dresser John Birkinshaw inside Bray Studios.

"We knew we were dealing with an iconic baddie," says Powell, referring to himself and Scott. Whether anybody else did was another matter.

"I wonder if Bolaji knew how important the role was... Perhaps he did after the event. I doubt it at the time."

Badejo wouldn't have been the only one -- when Sigourney Weaver signed up, she thought "Alien" was a " scrappy little independent film ." No one knew the film would go on to make over $100 million at the box office from a $11 million budget, or win an Academy Award for Allder, Giger and their team for Best Visual Effects.

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According to his brother, Badejo returned to Nigeria in 1980, and by 1983 was running his own art gallery. Badejo died in 1992, 39 years old, leaving behind two children.

Not one for the limelight, he was according to Allder "lovely, gentle and quiet," and yet, says Powell, "part of cinematic history."

He never did return for the "Alien" sequels, despite having the legal opportunity to do so. The 1979 hit was his only film credit.

"The fact that I played the part of Alien, for me, that's good enough."