Buckingham Palace said it would investigate staff working for Britain's royal family following an after-party in London which the Sun newspaper reported had ended in a "punch-up" and "bar brawl".
Workers attended an early evening reception at Buckingham Palace before heading to a nearby bar to carry on the celebrations.
But their partying got out of hand and police were called "after glasses were hurled and punches thrown", the Sun said.
Officers arrested a 24-year-old woman on suspicion of common assault, criminal damage and being drunk and disorderly at a central London bar on Tuesday evening, London's Metropolitan Police said.
"Officers were called to a bar in Victoria Street following reports that a customer had smashed glasses and attempted to assault a member of staff," a police spokesperson said.
The woman was released the following day after being handed a penalty notice for disorder, the spokesperson added.
Buckingham Palace said on Friday that palace officials were aware of an incident which had taken place outside the workplace following a reception at the official London residence of King Charles.
"While this was an informal social gathering, not an official Palace Christmas party, the facts will be fully investigated, with a robust disciplinary process followed in relation to individual staff and appropriate action taken," Buckingham Palace said in a statement.
- Reuters