MrBeast spent seven days underground.

YouTube star MrBeast has tested his endurance with an extreme stunt that saw him reduced to tears and sparked fears for his mental and physical health.

The online star, whose real name is Jimmy Donaldson, was buried alive in a specially-built coffin for seven days, monitored around the clock by cameras.

He was out to beat the record he set two years ago when he spent 50 hours below ground.

Donaldson was equipped with food and water and his custom-made home had enough room for limited movement, but found the greatest challenge was mental.

He became emotional at several points and told friends that he was going through “mental agony” as they rallied to keep his spirits up with jokes and stunts as they communicated through walkie-talkies.

Fans were also treated to some very intimate information, as Donaldson told followers at one point that he had filled up his supply of “pee bottles”.

He then went on to show his unusual solution to the problem.

When he finally emerged he was again emotional and said he felt a rush of blood as he stood up for the first time in seven days.

There were fears he might not be able to achieve the feat and concerns that he might develop blood clots, but he was given the all-clear.

A surprise was waiting for Donaldson when he was freed, with a celebration waiting for him to mark him reaching a mammoth 200 million subscribers.

“Please don’t try this at home lol,” he warned those watching his stunt.

MrBeast was the top creator Kiwis watched in 2022, coming in first place on a list that includes creators NichLmao, Airrack, Zhong, Stokes Twins, Ryan Traha, Brent Rivera, Jesser, Isaiah Photo and Sidemen.

His ‘World’s Most Dangerous Escape Room!’ video was the third-most popular clip overall.