The jacket is now all but sold out – one lowly jacket remains in an XS from Chinese retailer Lane Crawford – so if you’re quick you might be able to snap it up.
Kate was joined by Princes William and Harry at the event where they met with 150 volunteers from their Heads Together charity who are training for the London Marathon - and the royal trio also took to the track.
Kate and Wills gave it everything they had (even giving each other a good luck high-five before the race), but it was Prince Harry who took the title as the fastest royal – and from the look on Harry’s face we’d say that he was pretty chuffed with his win.
During a speech, William spoke of the trio’s hopes for the charity in reducing the stigma around mental health.
“We want to normalise mental health, we want to get people talking about it, to make it more normal and to reduce the stigma. What you are doing and having so many of you here today, you’ve already seen the benefit of joining in, by being part of this marathon, we want to make it a mental health marathon,” he said.
“You are crucial to making this happen and we can’t do it without you. We really hope your training goes very well. Good luck with the training and we look forward to seeing you on the big day.”