The actor who played the Xenomorph in “Alien” was a 6’10” man from Nigeria named Bolanji Badejo. He was discovered by a member of Ridley Scott’s casting team in a London pub in Soho. It was his only film credit. – WTF Fun Facts
Source: https://edition.cnn.com/2016/03/07/africa/bolaji-badejo-alien/index.html
They nicknamed the alien “Big Chap” the actor was a graphic designer.