A half-marathon runner from Sutton will compete dressed as a tiger as he tries to break a Guinness World Record in memory of his sister.
Damien Hersey, 31, will run 13.1 miles through Reading on March 2, aiming to be the fastest male athlete to complete the race dressed in animal costume.
The business analyst is also raising £1,000 in tribute to his sister Leighane, who died in April of last year aged 32 of Sudden Arrythmic Death Syndrome.
He said: "Prior to the death of my sister I did not fully understand the impact and prevalence of inherited heart conditions and sudden cardiac death, even after high publicity cases like Fabrice Muamba in 2012."
The previous record stands at 1 hour 31 minutes and 21 seconds, set by Travis Birch in Gosport, Hampshire, on November 17 of last year.
Mr Hersey tested his costume at a 10k run on February 16, recording himself using a camera mounted on a backpack in preparation for the real event.
He said: "The run went better than I had expected and I did not suffer as much as I thought I would from overheating.
"I can’t really see through the costume if the sun is in my eyes, so hopefully the British weather will help me out with a nice cool overcast day!"
He added that he had yet to attempt drinking while in costume.
The money raised will be donated to Cardiac Risk in the Young, a charity that promotes heart screening, bereavement support and medical research into heart disease.
Alison Cox, founder and chief executive of CRY, said: "At CRY we rely on the tremendous efforts of people like Damien to raise vital funds so we can increase awareness of sudden death in young people."
Those interested in donating can find more information at http://www.justgiving.com/damienhersey