Actor Daniel Radcliffe is interviewed on the NBC "Today" television programme in New York in this July file photo.
The Daily Mirror newspaper splashed the photos across the front page of its edition on Friday, saying the pictures were taken by fellow partygoer Wadia Tazi.
Tazi said he did not initially recognise the world-famous 20-year-old actor who, he said, told partygoers: "I love weed".
"Daniel looked spaced out and away with the fairies," Tazi told the newspaper.
"I was surprised by his behaviour.
"He is a kids' favourite. I'm not sure what his fans will make of it.
"At one point, a girl dragged him away, saying: 'Come on Daniel, follow me. You don't trust me, do you?'
"She pulled him into the toilet and started drawing a huge comedy beard on his face."
