A man who thought he was dating Katy Perry for the past six years has discovered the true identity of his online partner on a US television show.

Knoxville lothario Spencer Morrill was the latest star in the MTV show “Catfish”, which follows people who have been tricked into online romances.

Morrill apparently believed he had wooed pop star Katy Perry and adamantly told the program he was her one true love.

He had corresponded with a person for six years through emails, texts and even a phone call, but had never met face-to-face.

“It was an immediate connection. A million 'I love yous' back and forth. It was pretty cool," Morrill said of their relationship.

The show tracked down the woman he had apparently been communicating with, a British lesbian who was a huge Katy Perry fan.

Morrill was flown to England to confront his tormentor/love interest and even brought a diamond ring he had bought for Ms Perry.

Apparently the woman saw the error of her ways after the confrontation.