e end of a £2,000 darkness retreat experience which has seen the former world champion spend four days with no light at all.

Though not overly popular, the style of retreat is used by various sporting stars, including NFL star Aaron Rodgers, as a method of meditation to help athletes be alone with their thoughts.

It could be used before a big decision or as a method of strengthening the mind. Before Rodgers completed the process in February he said he was ‘really looking forward to it’.

On Monday, Joshua posted on social media: ‘Myself and [my friend] are about to embrace the darkness and solitude for four days (separate rooms).

‘Isolated with nothing to do except relax and clear the mind while being immersed in infinite darkness.’ He will emerge on Friday.

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Anthony Joshua has spent £2,000 to spend four days entirely alone in a pitch black dark room

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Aaron Rodgers was expected meditate and self-reflect without modern comforts, such as television, phones, or illumination on his retreat – the location of which is pictured here and is similar to the one used by Joshua

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PICTURED: An entrance to one of Sky Cave Retreats’ three dark rooms in southern Oregon, where Rodgers spent four days

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Joshua believes he will come out of the process without being bored due to the power of ‘the subconscious’ mind

The 34-year-old has been fed via food passed into the room but there has been no social interaction or light all week.

Rodgers, in March, said of his experience: ‘It was a great reset for me, for my body and my mind,’ the 39-year-old said of the four-day excursion. ‘Maybe a little bit longer than I needed. I feel like by the time I got to the fourth day, I was like, ”Alright, I’m ready to come out”.’

He also said he experienced hallucinations on day three of the retreat. Rodgers attended SkyCave retreat in Oregon for his trip and pictures on their website show a similar environment to the one Joshua will experience, with simple furnishings for his stay in total darkness.

Participants use a blacked out eye mask for the duration to ensure darkness throughout and are often filmed removing them at the end for social media purposes as they adjust back to daylight.

At Rodgers’ retreat he was given a yoga mat and a light switch if needed.

Coming towards the end of his career, Joshua has enjoyed immense success. From Olympic champion to two-time world champion to British icon, he’s done it all, but may have one or two regrets.

One regret is around the mental side of boxing. He told Men’s Health earlier this month that he used to think boxing was ‘all physical’ in his career. ‘Wake up, get on with your day, train,’ he said. ‘After losing fights, you question yourself and start realising the mental side is as important.’

He now has a psychologist with his career taking a different turn after back-to-back defeats to Oleksandr Usyk knocked him off top spot in the heavyweight division.

‘I would have been more disciplined,’ he said, reflecting on how his career may have gone if he’d considered mental health more earlier on in his career. ‘I don’t know if that would have made me better, but I would have done things more professionally.’

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The retreat Rodgers used also come with a yoga mat, and guests have access to a light switch if they need it

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He will emerge on Friday, with the room said to help with relaxation and processing thoughts

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NFL star Rodgers spent time in a pitch black room in February, and said it was a ‘great reset’ despite some hallucinations

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The Brit admitted to not taking the mental side of boxing seriously earlier on in his career

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He has fallen down the pecking order in the heavyweight division after back-to-back defeats to Oleksandr Usyk (left)

Though he has been alone with his thoughts, Joshua insisted before he went in that he won’t be bored.

‘There is so much stored in the subconscious,’ he said of what he expected to experience on the retreat.

‘What’s the worst that can happen? The worst is death so if it doesn’t do that, all good.

‘I said to them I was a bit scared and he said that’s a good thing. By October 20, I will be one of the coolest people, coming out after sitting for four days in the dark.’