The 'Stay with Me' hitmaker is due to take the stage at the MTV Video Music Awards this weekend and admits he is terrified about singing to a star-studded crowd including the 'Drunk in Love' hitmaker and Taylor Swift.
He told Capital FM: ''It's going to be so scary! Beyonce's going to be there, I might freak out. My main aim is to not sweat, because I'll be so nervous.
''I watch the VMAs every year, and have done from a very young age, so this is going to be a very surreal weekend. I get to run through it a few times, but I'm not going to kiss Madonna or stick my tongue out, so don't be expecting that!''
Sam added: ''The fact that I'm performing there feels like I've won already.''
It was recently confirmed that fellow Brit Jessie J will open the show with the first live performance of her new song 'Bang Bang' which features Nicki and Ariana.
Many ticket-holders couldn't get into the O2 Arena show on Tuesday night (September 19th) because they didn't bring photo ID to match their booking.
An album re-release, a new song and a documentary mark the singer's legacy this year.
The actor plays the titular hero in the forthcoming adaptation.