opened up about his "brutal" time in prison, admitting he surrounded himself with "tough boys" for protection.

The retired tennis player, 57, for hiding £2.5m worth of assets and loans to avoid paying debts.

The three-times Wimbledon men's singles champion was found guilty of four charges under the Insolvency Act and was found to be hiding hundreds of thousands of pounds worth of assets upon being declared bankrupt.

Becker, who is one of the celebrities appearing on the Netflix's Celebrity Bear Hunt, spoke about his experience in prison on BBC Radio 5 Live Breakfast.

"Whoever says that prison life isn't hard and isn't difficult, I think is lying," he said. "It was a very brutal ... a very, very different experience to what you see in the movies, what you've heard from stories."

He confessed that being a famous tennis player meant nothing while incarcerated, revealing inmates "fought every day" for survival.

Becker was surrounded by "murderers, by drug dealers, by rapists, by people smugglers, by dangerous criminals" during his time in Wandsworth and then Huntercombe prison.

"You fight every day for survival. Quickly, you have to surround yourself with the tough boys, as I would call it, because you need protection," he explained.

Becker revealed that his time behind bars "humbled him", adding: "I'm a survivor; I'm a tough cookie. I've taken the incarceration, but I've also taken the glory and if anything this made me a stronger, better man."

The six-time Grand Slam champion recalled his life being threatened twice.

"I thought I would lose my life in Wandsworth," Becker told German broadcaster Sat.1, per Bild. "Someone, a murderer I later found out, wanted my coat and he wanted money and he said he would kill me if he didn't get it.

"Then in Huntercombe, another murderer said they wanted to kill me. My food tray was shaking."

Becker shared how prison authorities tried to ensure his safety, allocating him a single cell and getting three experienced inmates to guide him behind bars.

"[The inmate] underestimated that other inmates would come to my help and threaten him," a tearful Becker added. "They saved my life."

More than two years out of prison, Becker has now joined the ultimate survival show as he attemps to outrun Bear Grylls on Celebrity Bear hunt, airing now on Netflix.