The troubled actress was apparently trying to befriend the singer at a roller disco.
Perry didn't appreciate the gesture and asked friends to keep Lohan away from her because she was acting "weird", The Sun reports.
"Lindsay followed Katy around trying to take a photo with her. Katy told her friends to keep her away as she was acting really weird," a source said.
The party was thrown by Perry for her stylist Johnny Wujek in California a couple of weeks ago.
Lohan recently held a slumber party with Lady GaGa and Lana Del Rey at the infamous Chateau Marmont hotel.
Perry is rumoured to be dating John Mayer.
Watch Digital Spy interview Katy Perry below: