The Princess of Wales underwent surgery earlier this year and is still recovering her health.
The awards ceremony for the prestigious BAFTA film awards kicked off in London on 18 February.
Prince William left his ailing wife Princess of Wales and attended the event at the Southbank Arts Centre. This is his first appearance at the BAFTAs without Kate Middleton since 2014.
The heir to the British throne has been president of the British Academy of Film and Television Arts since 2010, and therefore traditionally attends the BAFTA Awards. The exception was only the last two years.
Sources close to the royal family say that for Prince William the decision to attend the ceremony was not easy against the background of news about the illness of his father King Charles III.
Kate Middleton, 42, underwent elective surgery at a London hospital on 16 January.