According to his agent Thomas Bowington, Prowse died after a brief illness. CNN reported in 2018 that Prowse was being treated for prostate cancer.
"It is with great regret and heartbreaking sadness for us and millions of fans around the world to announce that our customer DAVE PROWSE M.B.E. has passed away at the age of 85," Bowington Management said on Twitter on Sunday.
"May the force always be with him!" His former agent, Thomas Bowington, said in a statement to the BBC.
"Although he is famous for playing a lot of monsters – to me and everyone who knew and worked with Dave, he was a hero in our lives."
Prowse wore the black suit and helmet to play Darth Vader, but it was actor James Earl Jones who provided the character's voice. The English accent of Prowse in the West Country was considered inappropriate for this part.
But it was his role as "Green Cross Code Man" from a UK road safety campaign that Prowse was most proud of. For this role he received an MBE in 2000 – a member of the Best Order of the British Empire.
Prowse was born into a working class family and grew up on an estate in Southmead in south-west England. He received a scholarship to the Bristol Grammar School.
He was passionate about bodybuilding and was crowned British weightlifting champion several times in the 1960s. According to the website IMDb, he made lifelong friends with actors Arnold Schwarzenegger during his weightlifting years.
His tall build and towering figure helped him get roles as monsters and villains in TV shows and movies. He played the monster in 1970 in "The Horror of Frankenstein" and in 1971 a bearded torturer in "Carry on Henry". That same year, in 1971, he appeared as a bodyguard in Stanley Kubrick's dystopian film "A Clockwork Orange".
In 1977, 1980 and 1983 he played Darth Vader in all three original films of "Star Wars".
Health and fitness remained an interest for Prowse, who also worked as a personal trainer for actors who played the role of Superman, including Christopher Reeve, and wrote a book called Fitness is Fun.
In 2011 he published an autobiography entitled "Straight from the Mouth of Power".