The singers were due to jet out of New York for a gig in Florida at the beginning of June (13), but the show was thrown into jeopardy when they arrived too late to board the plane.
George admits they were out all night and still drinking the following morning when they were supposed to be travelling across the U.S.
He tells Britain's Fabulous magazine, "Me and Jay missed our flight from New York to Florida... because we were still in the pub at 10am."
MCGuiness goes on to reveal they received an angry phone call from bandmate Nathan Sykes: "Nathan rang us, telling us about this certain line he expects us to adhere to. So we were like, fine, you're the boss, let's be professional from now on and I think we have been."
George insists they made it to Florida in time for the show, but they had to apologise to their bandmates: "We got on a later flight and went and did the gig and it was great. But we had to apologise to the boys, who were a bit p**sed off (angry) with us."