TV star ’s sister say her brother won’t be afraid to show his vulnerable side on his .

And says that the feat - which kicked off early this morning - will help smash “toxic masculinity stereotypes”.

She said: “That’s so important at the moment, to show vulnerability as a man. And I just think he’ll do that in such a brave way. We need more people breaking down that whole, like, toxic masculinity stereotype, don’t we? He is super open about who he is and being vulnerable and authentic.”

Sam is from last year’s stadium, Stamford Bridge in London, to the home of this year’s match, Old Trafford in Manchester.

Louise added that Sam will try to remain upbeat but she knows deep down he will suffer.

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She says: “I know my brother so well, so I’ll see the twinges in the eyes. I can tell when my brother’s suffering. I can tell when he’s lying. I can tell, you know, when you see it in his face.”

Louise, 35, is the older sister of Sam, 32. The pair was born in south Kensington, London, and both later starred in . The challenge is expected to take five days, and will also see him travel sections by bike.

Today he is expected to run 26 miles towards Hemel Hempstead, Herts, and then switch to two wheels to cycle a further 23 miles to Stadium MK in Milton Keynes, in Bucks.

Louise says Sam will struggle the most from a mental perspective. She added: “Those in between moments where it gets quiet and you’re left alone with your thoughts, that will be hard - because he’s not somebody that is ever quiet. He is always just throwing himself from, one busy work thing to the next - he’s not really someone that goes on holiday a lot either.

“He doesn’t like to remove himself from his comfort zone, and his routine. So, I think this will really throw him outside of his routine and, provide, some much needed, thinking time.”

Sam was yesterday joined on the first leg by who met him and , who supported Sam for the first leg of his challenge, at the first pit stop of the route.

Sam said: “We’ve done a half marathon and do you know what, it’s way better with Joel. I’ve actually just begged him to stay, he’s the best energy you could ask for and when you set off, you’ve just got so much nervous energy and you’ve got adrenaline going and stuff and it’s just really nice to be with someone like [Joel]. Joel is like my big brother so it’s just really nice to be with someone that I know so well, who can sort of take you on the journey.”

Josie pointed out the plasters on Sam’s legs and he replied: “I’ve just got shin splints but I think loads of people get shin splints. When you’re training for these things, I don’t think you’re ever going to get to the start line without a few niggles here and there." Follow Sam's challenge here: