The Queen has spent a night in hospital after cancelling her visit to Northern Ireland, Buckingham Palace has said.
A spokesperson said the monarch went to hospital for “preliminary investigations” on Wednesday but returned to Windsor Castle on Thursday.
The Queen, 95, was seen by specialists at the private King Edward VII’s Hospital in central London. Her admittance is understood not to have been related to coronavirus.
The spokesperson said: “Following medical advice to rest for a few days, The Queen attended hospital on Wednesday afternoon for some preliminary investigations, returning to Windsor Castle at lunchtime today, and remains in good spirits.”
The PA News agency reported it is understood the overnight stay was for practical reasons and the Queen was back at her desk on Thursday afternoon and was undertaking light duties.
The head of state’s stay was kept a secret but the Palace issued a statement on Thursday evening after The Sun newspaper broke the news.
The development was not announced at the time as she was due to attend for only a short stay. Protecting the Queen’s medical privacy was also a consideration.
She was said to be disappointed not to be able to travel to Northern Ireland on Wednesday, and reluctantly heeded the advice of her doctors.
The nation’s longest reigning monarch, whose husband Prince Philip died just six months ago, has had a busy schedule since returning from Balmoral at the start of October.
She hosted a major Global Investment summit at Windsor Castle on Tuesday evening, where she looked bright and cheerful as she carried out her royal duties.
This article originally appeared on HuffPost UK and has been updated.