Oscar Pistorius is reportedly unrecognisable in prison after a string of lifestyle changes.

The former Olympic athlete, known as 'Blade Runner', remains behind bars in South Africa for the murder of his girlfriend Reeva Steenkamp in 2013.

Pistorius, 33, shot model Reeva, 29, through their bathroom door during the night following Valentine's Day - though he told the court he believed there was a burgular.

His former school headteacher Bill Schroder, 76, has been visiting Pistorius sporadically in prison.

And after his most recent trip, he has explained that the ex-athlete has taken on a radical new look.

Pistorius pictured after he was sentenced to prison in 2016

He told the Sun on Sunday that Pistorius has now grown a bushy beard - and his figure is looking a little more plump too.

He has reportedly since given up on all exercise and is also now a smoker, completely changing his complexion and making him unrecognisable from when he first went to jail in 2016.

Because he is behind bars, there are no photos of his current look.

In another lifestyle change, Pistorius has also turned to God and is preaching to his fellow in-mates.

Pistorius pictured alongside Steenkamp during their relationship
Pistorius arrives at court before he was sentenced to prison in 2016

Reports in 2018 claimed that he has become a spiritual leader at the Atteridgeville Correctional Centre in Pretoria.

His father, Henke, said at the time: “I have no doubt that Oscar has changed the environment in the prison for the better, he is helping to mediate between people and is having a positive influence.

“He can feel he is making a difference to others who really needed a difference to be made — to give their lives meaning, purpose and some hope. As a result, things have also improved for him.

“It's a wonderful story. They are hardcore chaps, the problem people in the prison, but now they are all meeting to follow the Bible once or twice a week.”

Pistorius pictured during his appearance at the 2012 Olympic Games
Pistorius' look has completely changed, according to his former teacher

Talking about his visit to Pistorius earlier this year, former teacher Mr Schroder said: “What he really, really wants is forgiveness.

“I said to him that if he had killed my daughter I doubt I would forgive him.

“He is more concerned about forgiveness than actually getting out on parole. In fact, he has a real fear about getting parole as he knows they’ll be a backlash.”