Kevin Sinfield has said he doesn't care how long it takes him to complete the first ever Rob Burrow Leeds Marathon, as "the longer it takes, the more time I get to spend with Rob".
The pair are completing the inaugural marathon together, with Sinfield pushing his former Leeds Rhinos teammate around the 26-mile course, to raise money for motor neurone disease (MND) research.
It comes after rugby league legend Burrow was diagnosed with the disease in 2019.
Sinfield told ITV Calendar: "There's no pressure. The longer it takes for us to do, the more time we get together so we'll enjoy it.
"Hopefully people come and say hello, smile and we'll have a good day."
More than 12,000 people started the run around the city at 9am today, with a further 3,000 people beginning the half marathon an hour later.
The aim is to raise money for MND charities and to build a new MND centre in Leeds.
Sinfield has already completed a series of gruelling challenges to raise money for the cause, in honour of his friend. Most recently, he ran seven marathons in seven days.
He said: "The last couple of years have been incredible.
"What Rob and Lindsey have been able to do and the support from the MND community has been unbelievable.
"There's been over £3 million raised already and that will help charities all over the UK, but obviously the MND charities are really, really important.
"Rob's been absolutely amazing in his fight and his campaigning and it's an honour to run with him today."
Want a quick and expert briefing on the biggest news stories? Listen to our latest podcasts to find out What You Need To Know.