LONDON - Who would win a race between Prince William, Prince Harry and the Duchess of Cambridge Kate Middleton?

Answer: Prince Harry, who beat his older brother to the finishing line at the Queen Elizabeth Olympic Park on Sunday (Feb 5).

Prince William and his wife shared a sweet embrace after the race.

Cheered on by track stars and amateur runners training for April's London Marathon, the royal trio were competing in a 50m sprint to promote Heads Together, a mental health campaign.

Heads Together is the chosen charity for this year's marathon.

The three royals have long supported the campaign, which aims to promote awareness and end stigmas about mental health.

"Their Royal Highnesses are championing the #HeadsTogether campaign to urge people to talk about mental health," Kensington Palace said in a tweet.