Katy Perry's "heart goes out" to the Catfish victim who believed he had been dating her online.

U.S. TV show Catfish, hosted by Nev Schulman and Max Joseph, documents the lies people adopt when using social media and online dating.

An episode of the series last week (17Aug16) told the tale of Knoxville man Spencer Morrill, who was under the impression he had been in an online relationship with Roar singer Katy for the past six years.

However, following Nev and Max's investigations, he discovered he had been catfished by a woman named Harriet, who lives in England.

As she appeared on SiriusXM radio show The Morning Mash Up on Wednesday (24Aug16), Katy revealed her sadness over the situation.

"You know, like, my heart goes out to him actually because anybody that's been fooled like that or just, you know, people have dreams, and people live in different parts of world where not everything is always so accessible," she said. "Like we live on the coast, and we, you know, get stuff in a way that some other people don't get, and I felt bad for him, and so I didn't really like to indulge in that."

The singer said she found out about Spencer’s story because someone sent her an article about what happened on the show.

"Yes someone sent me a link, and I didn't actually read through it because I just think it's really unfortunate and very sad," she added.

After the episode aired, Harriet boasted about her catfishing of Spencer on Twitter, dividing opinion with her bragging. Spencer, meanwhile, told Nev and Max that he was guilty of being gullible in believing he was dating Katy. He added that he won't be looking for love online any more.

Catfish was originally a 2010 documentary film which followed Nev as he discovered a girl he had been chatting to online was actually an older woman called Angela. Following the success of the film, Nev has fronted five seasons and 69 episodes of a TV series spin-off, with versions also being created in various countries worldwide.