RPatz was hanging out with the Roar singer at the premiere of his new movie The Rover.
He traded in his orange trousers for an all black outfit, while Katy was decked out in a sparkly minidress.
According to a source for Radar Online, his eyes "lit up" when he saw her.
"She looked gorgeous in a lace sequin black mini-dress, and they hugged and kissed. 'He kept kissing her the entire night."
With speculation that Katy may still be seeing DJ Diplo, we're sceptical about these rumours, especially since she once said she was proud that they'd never slept together.
Then again, the pair have always seemed close - remember when they got drunk and sang karaoke together?
There's just part of us that thinks Rob isn't bad boy enough for her, maybe he should grow his hair...
Perhaps some of the songs on his new album will be about her not KStew.
Robert Pattinson for Dior Homme
Do you think they're dating? Tweet us @handbagcom
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