Britain's Prince William and Catherine visit Royal Liverpool University hospital in Liverpool
Prince William has long been an advocate of mental health through his and Kate Middleton's Heads Together charity founded in 2016. Reuters

Prince William gave Emma Webb quite a wonderful surprise when he joined her for day 13 of her charity walk to raise awareness for mental health.

She was walking from Wales to London to pay tribute to her daughter Brodie, 16, who died by suicide in March 2020. As she stopped to pull a life-size horse called "Miles" in honour of her daughter's passion for horse riding, the Prince of Wales walked up in front of her and quietly said, "Boo".

Webb jumped up in surprise and after realising who was in front of her, she put her hands up to her face in glee and shared a hug with the royal. She shared a video from the encounter on X which the dad-of-three reposted on The Prince and Princess of Wales account.

She wrote: "So day 13...and this happened 🥰 How very, very kind and supportive ♥️ Keep watching for the biggest surprise."

Meanwhile, Prince William wrote: "What an incredible thing Emma is doing to raise awareness of youth suicide, in memory of her daughter Brodie. Very special to be able to join her for part of her journey this morning." He then signed the message "W".

Webb shared in an interview with the Daily Mail that she was aware that Prince William had seen what she was doing from the news. But she had no idea that he was "going to turn up on the streets of Slough" and walk with her.

"It was amazing! He appeared from behind the horse and shouted, 'Boo,' at me! I turned around, and I was just gobsmacked that he was stood there. Me, a little old Welsh lady from Newport with a plastic horse and the Prince of Wales is just stood in front of me!" she said.

Webb admitted that she "didn't really know what to do" when she saw him. But when she noticed him initiate a hug then she just went right for it.

She said: "He put his arms out and I thought, 'Right, I'm going to have a nice hug,' so he gave me a nice hug, or a Welsh cwtch! To have a hug from the future king, it's just unthinkable, it was like an out-of-body experience."

Webb shared that she and the mother she was with who also lost a daughter to suicide talked to Prince William for 20 minutes about mental health. She said he even offered to push Miles. She gushed that it was amazing that the royal came out to recognise what they were trying to do. She said: "You can't get a more supportive backer than the Prince of Wales, so it really means everything to me that he came out today."

If you or someone you know is having thoughts about suicide, the Samaritans provide a free support service for those who need to talk to someone in the UK and Republic of Ireland. Visit Samaritans.org or call 116 123 (UK) or 116 123 (ROI), 24 hours a day, 365 days a year. Visit this website to find a support phone number in your country.