The group, who are gearing up for the release of their fifth studio LP, admitted that they would also "hammer" tequila with Austin - known for his work with Madonna, Sugababes and Pink.
Drummer Tom Fletcher told The Sun: "Dallas introduced us to Patron tequila. He almost killed us on a couple of occasions - it's lethal. He also really likes strip joints, so we'd hammer the tequila and then head off to these clubs.
"One night we ended up going round Elton John's house in Atlanta for dinner with Dallas. It was a great time."
Discussing their latest as-yet-untitled record, Danny Jones said: "Our influences have been people like Bruce Springsteen and The Beatles, but this time we took inspiration from artists we'd never tapped into."
The LP will also feature two tracks co-written with Taio Cruz, called 'Shine A Light' and 'I'll Be Your Man'.
McFly's new single 'Party Girl' is scheduled for release in early September.