Helensburgh's Adam Keighran will have some extra cosy weight to carry on September 15, when he takes part in the annual event, Blackmores Sydney Running Festival.
Mr Keighran will dress in his highland best, and go a step further, attempting to break a Guinness World Records title for the 'astest marathon dressed in a highland dress'.
He will be supporting The Miracle Babies Foundation, a charity that assists premature babies and their families.
Being born at 27 weeks himself, the cause it something close to his heart.
To be successful, he will need to complete the marathon of a time before three hours and 21 minutes, which is the current record.