Matt Roberts was joined by Puff the Marathon Dragon (Asthma UK), Chester the Squirrel (Royal Parks Foundation) and Stamford the Lion (Help a London Child and Right to Play), as 30 fully dressed mascots gathered to get in shape for the 10 October event.
Roberts put the mascots through a gruelling work out to help them cope with the 13.1 mile route while wearing their heavy costumes.
The route takes in four of London’s Royal Parks, starting in Hyde Park before moving through St James’, Kensington Gardens and Green Park.
Public spaces are still available fore runners wishing to take part without the costume.
It is the third year the event has been held and so far it has raised over £4.5 million.
To register visit www.royalparkshalf.com