Prince Harry joins the winning runners at the London Marathon

Cheeky Prince Harry has told the nation that his brother William and wife Kate Middleton will be taking part in the London Marathon 2013.

The 27-year-old made the joke on live television at the finishing line of the 26.2 mile race, which had 37,500 successful participants this year. 

'What's fantastic is that my brother and his wife will be doing it next year - I think,' said Harry

He then laughed: 'He's going to have to now, isn't he?'

Wills, 29, and Kate, 30, wouldn't be the first royals to sign up to the run - Princess Beatrice, 23, took part in 2010. 

But it seems the couple are as yet undecided.

'Harry's comments were made in jest,' a Clarence House spokesman tells The Sun.

'It's too early to say if the Duke and Duchess of Cambridge will take part next year.'

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Esme Riley