A man is in hospital in a critical condition with a fractured skull after allegedly being attacked in an Adelaide nightclub.

The 24-year-old Brahma Lodge man was allegedly punched at Zhivago on Currie St at about 9.45pm yesterday.

He suffered a fractured skull and was taken to the Royal Adelaide Hospital by ambulance, where he remains in intensive care.

No arrests have yet been made over the incident, but police have appealed for anyone with information to contact Crimestoppers.

The nightclub released a statement this afternoon and said the alleged attack appears to have been an isolated incident involving two individuals.

“Zhivago is co-operating fully with SA Police and has made its CCTV vision available to assist with their investigations,” the statement said.