Leaving the premiere of her film Part Of Me last night, the singer was snapped with some tissues poking out from her cleavage.
Considering she's been quoted by The Mirror as wanting to have "smaller boobs", it's a little surprising that she'd be padding her bra.
Our guess? She got a bit emotional during the screening, which is said to be a real tear-jerker.
Either way, wouldn't you think to chuck your snot rags in a bin before approaching the paps?
Katy was joined on the night by fellow pop stars Justin Bieber, Selena Gomez and actor Robert Pattinson - who had a little trouble joining them in the van leaving the event.