Miley Cyrus to Katy Perry: Good Thing John Mayer is Your Ex!

Miley Cyrus plays it cool as she does some shopping at Bed Bath & Beyond on Wednesday (March 5) in Los Angeles.

The 21-year-old entertainer was on a short break from her Bangerz tour and was joined by a guy pal.

PHOTOS: Check out the latest pics of Miley Cyrus

Later that day, Miley took to Twitter to call out Katy Perry and John Mayer after she said she didn’t know where Miley‘s tongue had been.

“Girl if ur worried abt where tongues have been good thing ur ex boo is ur EX BOO cause we ALL know where THAT been pic,” Miley tweeted. LOL!

In case you missed it, check out the two pop stars’ recent lip-lock!