Catfish shocker: Man thought he was dating Katy Perry for six years

In an episode of Catfish, Spencer believes he's been in an online relationship with Katy Perry. Photo / YouTube, Getty Images

An American man believed he was dating Katy Perry for six years, despite the chart-topping pop star marrying Russell Brand and dating several other celebrities during their time together.

The ruse was uncovered by the presenters of Catfish Max and Nev, who use their MTV show to uncover online scams and fake relationships.

The man, called Spencer, believed he'd been having an online relationship with Perry for six years, despite never having met her and only talking to her on the phone once.

"She's awesome. Katy's funnier than I am, she's smarter than I am. I don't know how many people give her credit for that, but she's very intelligent. Katy's full of life, huge heart," Spencer told the show.

The Tennessee resident believed he'd been sent unreleased songs by Perry, and had traded emails, text messages and videos with her. He had bought her an engagement ring using "25 per cent" of his savings, and said they said, "I love you" to each other all the time.

Their one exchange over the phone, to a number he had for her in Canada, had cost him US$270 ($370), he said.

The Sun reported the pair traced Spencer's "Katy Perry" and discovered she was in fact a gay British woman called Harriet who had spent six years posing as the pop star.

When they caught up with her, they discovered she had no interest in men and she reportedly wasn't fazed by her behaviour being uncovered.

"I can't really change what I did, but I understand it was really wrong," the Sun reported her as saying.

Despite breaking the news to Spencer, the duo discovered he was still emailing the address when they returned months after the ruse was revealed to him.

Perry married Russell Brand in 2010, but they divorced in 2012. Since then, she has dated John Mayer and is now seeing Orlando Bloom