Ed Sheeran says Psy is a "monster" on a night out.

The British singer is gearing up for the release of his second album x later this month, which has already spawned number-one hit Sing. Ed"s video for the track was inspired by a night out with the South Korean popstar, which the 23-year-old won"t be forgetting in a hurry.

"I went out on this night out with Psy and everyone was wearing a Psy mask in a Korean restaurant and they were all Korean and all wearing a Psy mask and I didn’t know which one was Psy, I had no clue,” he reminisced to Live from MTV. “I eventually found out who Psy was and he’s just a monster when it comes to… there’s this Korean drink called Soju and so anyway, I had this night out and that’s what inspired the Sing video with all the dancing and karaoke and stuff.”

It seems the late-night antics with the 36-year-old musician have helped Ed form a close bond with him. They"re still in touch now, and he even made his own version of the redheaded star"s top hit.

“He just did a remix for Sing, and it’s sick, and it’s the coolest thing I’ve ever heard,” Ed gushed. “Just before [I] came in here he texted me being like: ‘question mark, question mark, question mark,’ so I need to find out what he means.”

Ed added that he"s not sure if Psy"s take on Sing will ever be made public.

x follows his number-one debut album + and will be supported by a tour.