Taylor Swift can clear the "jam" between her and Katy Perry.

That was what singer Perry suggested during her Carpool Karaoke segment with talk-show host James Corden that aired on Monday's Late Late Show Primetime Special.

He had asked Perry, 32, about the rumoured bad blood between the two superstar singers, reported E! News.

"There's a situation," Perry conceded. "Honestly, it's like she started it and it's time for her to finish it."

The discord has apparently lasted years, with speculation that Taylor's 2014 hit Bad Blood is her swipe at Perry. It contains the stinging line: "I was thinking that you could be trusted."

In the Carpool segment, Perry said: "I tried to talk to her about it and she wouldn't speak to me.

"It was a full shutdown and then she writes a song about me, and I'm like, okay, cool, cool, cool, that's how you want to deal with it? Karma."

But Perry - who is reportedly getting US$25 million (S$34.7 million) to be a judge on the rebooted American Idol show - is ready for a ceasefire, noted The Hollywood Reporter.

Asked if she can forget her beef with what Swift, 27, had supposedly done, she said "100 per cent" - as long as she receives some indication, say, a text from Swift, saying "the beef is off the grill" as Corden had put it himself.

"I think that women together - not divided, with none of this petty s*** - will heal the world."

But not before she has had the last word. Appearing in The Tonight Show over the weekend, talk-show host Jimmy Fallon asked her whether her new single Swish Swish is "about anyone we know".

Her steely reply: "I think it's a great anthem for people whenever someone's trying to hold them down or bully them."