More than 2000 Santas are set to descend on Battersea Park in south London later on!
The Original London Santa Run is a 6km fun run and starts at 10am.
It helps to raise funds for Disability Snowsport UK, a charity that helps people with disabilities take part in snowsports.
12 and a half thousand people followed in the steps of their 2012 heroes, to take part in the five-mile 'National Lottery Anniversary Run'.
Around 15,000 people followed in the footsteps of medal-winning stars today when they took part in a race at the Olympic Stadium, crossing the finish line.
Olympic gold medallist Sir Chris Hoy joked that he had not taken part in today's National Lottery run at the Olympic Stadium because he is "better on wheels than on foot".
Sir Chris said the run was a chance to "thank the British public".
Marathon world record-holder Paula Radcliffe told ITV News that she was "excited" to return to the Olympic Stadium, as thousands gather to take part in the National Lottery Anniversary Run.
Radcliffe thanked the British public and Olympic committee for "continuing to support sports".
The scene is set for today's National Lottery Anniversary Race, which is taking place at the Olympic Park in Stratford, east London: