Justin Bieber played the piano at a pub in Russell, New Zealand

Justin Bieber played the piano for about 50 diners at the Duke of Marlborough Hotel in Russell, New Zealand, last Thursday. Most of them never knew it was him, the hotel’s co-owner, Anton Haagh, told RNZ.

Bieber wasn’t staying at the hotel. He came into the restaurant in the afternoon with seven other people for a few beers and some seafood, including oysters and ika mata, a raw fish dish.

“He saw our red piano, and it’s a baby grand piano in the corner, and he just jumped on and started knocking out a few tunes,” Haagh said.

Bieber lifted the lid of the piano so the people in the restaurant could not see his face. He played modern songs, none of them his own, and he did not sing.

Haagh said only four or five people “clocked him”, most of them on their way to the toilet, which took them past the piano. “As they walked past, they sort of went, ‘Whoa,’ turned around and went, ‘Whoa.’”

He asked each of them to leave Bieber alone. “You can either spoil the moment and take photos and make a scene, or why don’t you just sit down and just relax and enjoy it?”

Haagh’s daughter was asked to wait on the group. He said she was “absolutely fizzing” but kept it together.

Before the group left, they rang the ship’s bell that hangs in the restaurant, co-owner Bridgit Haagh told RNZ’s Morning Report. Anyone who rings it has to buy the whole bar a drink, and they did.

They left before word got round. Anton Haagh said 30 to 40 people turned up afterwards hoping to see him.

On Sunday Bieber posted a photo of himself at the piano on Instagram. Haagh said the hotel usually keeps quiet about famous guests and has not decided whether to mark the visit.