Watch: The Duke of Cambridge speaks about the Duke of Edinburgh.
The Duke of Cambridge gave a reassuring wink when asked about the health of his grandfather at a King's Lynn vaccination centre today.
Prince William said the 99-year-old was "OK" and "they're keeping an eye on him" and gave a wink.
Prince William popped by to meet those getting a jab and the staff and volunteers keeping the centre running.
Watch more from our reporter Raveena Ghattaura
The Duke of Cambridge attended the site at the Corn Exchange to find out about the roles people are playing in the fight against coronavirus.
Last week the Duke of Cambridge paid tribute to a "much loved" Norfolk nurse who died after contracting Covid-19.
The visit comes as his grandfather, the Duke of Edinburgh, spent a sixth night in a London hospital.
Officials gave no update on the 99-year-old’s condition, having previously said he was “in good spirits”.