Speaking to Reveal at the Capital FM Summertime ball at Wembley, the boyband's Adam Pitts and Joel Peat reminised about partying with Katy, 28, last year.
"After the Summertime Ball last year we ended up going out with Katy Perry - that was cool," said Joel.
"She was very cool but she couldn't keep up. No-one can, no-one is as big drinkers as us lot, we take the crown!"
To prove their point, Lawson teamed up with fellow party-animals The Wanted as they hit Mahiki nightclub in London's Mayfair after the concert.