Katy Perry is planning to give Miley Cyrus ''the biggest spanking'' when she sees her.

The 'Dark Horse' hitmaker made the cheeky threat to 'Wrecking Ball' star Miley in response to a dig about her ex-boyfriend, John Mayer, earlier today.

The incident started when Katy said she pulled away from kissing Miley at a recent concert because she didn't know where her tongue had been, and she responded by writing on Twitter: ''Girl if ur worried abt where tongues have been good thing ur ex boo [boyfriend] is ur EX BOO cause we ALL know where THAT [tongue] been (sic)''

Katy then responded: ''@MileyCyrus Oooo gurrrl I'm gonna give you the BIGGEST spanking when I see you in the UK bb!''

Katy is currently in Australia on a promotional tour for her latest album 'Prism', while Miley is in the US on the first leg of her Bangerz Tour, which will head to Europe later in Spring.

Katy was in a relationship with guitarist and singer John Mayer until last month, when they split over their conflicting schedules.

The 'Gravity' star has been known as a ladies' man and has previously been linked to Jennifer Aniston, Taylor Swift, Jessica Simpson, Jennifer Love Hewitt, Vanessa Carlton, Cameron Diaz and Rashida Jones.