David Beckham on Saturday expressed regret to have missed this year's Earthshot Prize award ceremony in Brazil.
Taking to Instagram stories, the former football star shared a video of the British heir to the throne and wrote, "sad to miss Earthshot Prize in Rio this week. 5 years in.. the momentum is unstoppable."
In the video shared by Beckham, William is delivering a speech at the event which took place on Wednesday.
David Beckham was knighted by King Charles at a ceremony held at Windsor Castle earlier this week after William had left for Brazil.
The 50-year-old former England soccer captain received the honour at the royal residence, more than 20 years after he was awarded a separate royal honour recognising his contribution to football.
Beckham, a lifelong admirer of the royal family, was dressed in a suit designed by his wife, Victoria Beckham, a fashion designer and former member of the Spice Girls pop band.
Born in east London, Beckham made his Premier League debut for Manchester United in 1995, two years after he joined as a trainee. He went on to win six league titles, two FA Cups and the Champions League with the club, before playing for Real Madrid, LA Galaxy, AC Milan and Paris Saint-Germain.