A woman created a security scare after trespassing into Prince Andrew's home, police confirmed.
The 43-year-old intruder trespassed into the Duke of York's home at Royal Lodge in Windsor Great Park on Monday morning.
She was arrested by Thames Valley police but has since been released to be sectioned under the Mental Health Act.
It has been reported by the Sun newspaper that the "smartly-dressed" woman turned up at the Royal Lodge claiming to have a lunch appointment with Prince Andrew.
She was waved through the gates and spent some time wandering in the gardens before entering the house, the newspaper reported, citing an unnamed source.
ITV News Correspondent Rebecca Barry said something 'clearly went wrong' after a woman talked her way past security guards
Police were said to be called after she asked a member of staff in the lobby where the duke was. When police arrived, she reportedly told officers she was Prince Andrew's fiance.
A statement by police read: "Thames Valley Police were called to the Royal Lodge at Windsor Great Park on Monday morning to reports of a female trespasser.
"The woman, aged 43, was intercepted and arrested.
"She was subsequently de-arrested and has been sectioned under Section 136 of the Mental Health Act.
The Royal Rota - listen to the discussion on the Duke of Edinburgh's funeral service
"The investigation into the incident continues, but there was no risk to any individual on the site. Due to the female being sectioned, we will not be commenting further at this time."
Buckingham Palace declined to comment on security matters.
Prince Andrew and former wife Sarah Ferguson have lived at the Royal Lodge since 2004.
The Royal Lodge was previously the Queen Mother's home, until she died in 2002.