Joshua, who is currently riding the wave after his sensational knockout victory over Francis Ngannou in March, was course-side on sponsorship duty, handing out drinks and chatting with runners.

The Brit could be seen wearing a dark blue Lucozade hoodie, and one video shared by the drinks brand shows him giving advice to one participant on how to finish the race.

Anthony Joshua was seen handing out Lucozade and providing encouragement to London Marathon runners on Sunday

The British boxer shared a wonderful experience with a runner who was suffering.

‘Listen, this is where you dig deep,’ AJ is seen advising a runner as he embraces the opponent, who is clad entirely in orange.

‘I’m just mentally blown apart,’ the runner replied.

Joshua continues: “Yeah, but listen. It’s alright if you know you’ve been mentally blown up. It’s all in your mind, right? So if you feel like you’ve been blown up, start rebuilding right away.

‘Take a quick summary, stroll for two minutes, and finish the race, bro. govern your thoughts; govern your mind. Let’s go.

The runner, who is seen happily getting a cup of Lucozade from Joshua, then fist bumps the heavyweight before continuing to run.

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A number of other competitors also stopped for some words of wisdom from the two-time world champion

Joshua is still waiting to find out his next in-ring opponent having beaten Francis Ngannou (right) in March

Joshua continues to wait to find out his next opponent for the boxing ring, with it expected he will take on the winner of Tyson Fury’s unification bout against Oleksandr Usyk.

The two heavyweights will do battle in Saudi Arabia on May 18, with Fury set to make ‘some adjustments’ for the bout as he looks to recover from a narrow win over Ngannou.

The Brit scraped past the former MMA star in October, leading to fans calling for him to be wary when he faces Usyk, before a potential clash for the ages against Joshua to follow.