The 58-year old who often performs at Spring Harvest told the judges why he finally decided to appear on the popular talent show.
"I have thought about it and I've chickened out and so I got to the point this year where I thought, 'face your fears and do it' and so I'm here."
He got emotional as he opened up about the toil his profession has had on his family as doing gigs takes up a lot of his time.
"I really just want to make them proud," he said fighting back tears.
"I know it sounds corny – sorry!"
He revealed he had not brought anyone with him, as it would make him "too nervous" to perform.
For his trick, Archer asked judge David Walliams to join him on the stage and showed him a series of cards with different drinks written on them.
John received a standing ovation from all the judges and audience after pulling off a trick that had seemed destined to fail.
Britain's Got Talent's semi-finals will air live on ITV at 7:30pm on Monday.
Stay up to date with the latest news stories from a Christian perspective. Sign up to our daily newsletter and receive more stories like this straight to your inbox every morning.