British Queen Elizabeth II spent a night in hospital Wednesday, said Buckingham Palace Thursday, Trend reports citing Xinhua.
A Buckingham Palace spokesman said that following medical advice to rest for a few days, the Queen attended hospital on Wednesday afternoon "for some preliminary investigations."
She has returned to Windsor Castle at lunchtime Thursday, "and remains in good spirits," the spokesman said.
The 95-year-old monarch had to cancel a visit to Northern Ireland on Wednesday after she was given medical advice to rest for a few days.
The Buckingham Palace said Wednesday in a statement that she was "disappointed" after cancelling the two-day trip in Northern Ireland where she had been due to undertake a series of engagements.
On Tuesday evening, she attended an event at the Windsor Castle, where she was seen alongside Princes Charles and William, and Prime Minister Boris Johnson.