John Mayerwas left a little red faced yesterday (December 17) after dropping the F-bomb Katy Perry.

The superstar couple were appearing on US TV show Good Morning America, with Mayer making the error when discussing their collaboration Who You Love.

When asked what it was like working with K-Pez, the singer-songwriter replied: "I come in the studio and she plays stuff... And then I'll hear a melody, cause she'll be writing something, I'll hear a melody and I'll be like, 'Don't! Don't!' She was f**king..."

Mayer soon realised his mistake, with Perry swiftly chipping in: "Or he'll just pick up a guitar and play something."

John continued: "But I'll go, 'Come here, come here, come here, I sang this into my iPhone while you were in there, just check it out'. [And Katy says] 'Oh, I'll do that!' and I'm like 'OK, good, good good'."

As well as swearing on live TV, the 36-year old and Perry were also on hand to share the music video for Who You Love - which sees the couple riding a mechanical bull and singing together.

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