JOHANNESBURG - The news that racing car driver Gugu Zulu has died has been met with anguish, shock and sadness.

The 38-year-old was climbing Mount Kilimanjaro in Tanzania with his wife, Letshego Zulu, and other well-known South Africans as part of the Trek4Mandela initiative.

Two days ago he posted an Instagram photo of him and his wife saying she was doing well, but he was experiencing flu-like symptoms.

Made it though day2. My wife is doing fabulous, she has even learnt the local language. Am having flu like symptoms and struggling with the mountain but taking it step by step!! Today we managed to see our destination and our camp is literary above the clouds!! Bring day 3!! #AdventureCouple #AdventureLiving #Trek4Mandela #Caring4Girls #Thule #Fitbit

A photo posted by Gugu Zulu (@guguzulu) on Jul 15, 2016 at 4:15pm PDT

The Nelson Mandela Foundation's Neeran Naidoo said, "We spoke to two members this morning and we understand he had problems breathing last night. The medical team on site put him onto a drip and brought him down from the mountain. They tried everything possible to save his life but unfortunately we lost Gugu this morning."

GALLERY: Celebrating the life of Gugu Zulu

Sports Minister Fikile Mbalula is among the people who have reacted with shock and sadness.

Tragic news of the passing of Gugu Zulu announced by @NelsonMandela Foundation, Condolences to his family & friends pic.twitter.com/LqXEUHLKOv

— RSA Min of Sport (@MbalulaFikile) July 18, 2016

Mbalula says this is a major loss for South Africa.

He described Zulu as a dynamic and unselfish individual who died while pursuing a good cause.

"It is a great loss. We have lost an individual who has made a name for himself and used that name to pursue a good cause."

People took to social media to express disbelief at the news.

This is terribly sad! RIP #GuguZulu! https://t.co/jwIGECD0mn

— Leo G. Smit (@LeoGSmit) July 18, 2016

What??? #GuguZulu passed on? Ohh no. What a happy soul he was. Recently got married. New baby. #adventurecouple. Saddening news.

— BlackExcellence (@TshepoMongale) July 18, 2016

So sad, so tragic. Today #GuguZulu celebrates Tata's Birthday with him up in heaven. They're smiling while looking down on all the good.

— Wayne Hart (@WayneHartSA) July 18, 2016

Heartbreaking news about #GuguZulu's passing. A truly inspiring soul. Love and comfort to his wife and family. May he rest in peace.

— Khanyi Dhlomo (@KhanyiDhlomo) July 18, 2016

Condolences to the family of Motorsport champion #GuguZulu who died while climbing Mt. Kilimanjaro for #MandelaDay pic.twitter.com/KnntzKkCsA

— South African Gov (@GovernmentZA) July 18, 2016

We are completely heartbroken. RIP #GuguZulu. Our thoughts and prayers are with your beloved family. pic.twitter.com/UG8Fd853wM

— Topbilling (@SABC3Topbilling) July 18, 2016

Honestly one of the nicest humans I have ever met. Down to earth, friendly, so likable. Absolutely devastated. Is this for real? #GuguZulu

— Jason Von Berg (@JasonVonBerg) July 18, 2016

Oh #GuguZulu bakithi, im shaking with fear and disbelief, may your soul find rest

— tumisangkhunou (@tumeash) July 18, 2016

I am so devastated by this news. A great life cut short: Driver #GuguZulu dies before summiting Mount Kilimanjaro https://t.co/Z2gPUEtI8Z

— Amy Ford (@Lamyfrog) July 18, 2016

The Nelson Mandela Foundation also extended its sincere condolences to the Zulu family.

In a statement by the foundation this morning, CEO of the Nelson Mandela Foundation Sello Hatang said, "I am devastated. I knew him well. I recruited him to climb Kilimanjaro. The last thing he said to me at the airport before he left last week was that he wanted to speak about doing other Mandela Day projects. I feel a huge sense of loss."

Zulu's wife was with him during his final moments on the mountain.

They were often referred to as the 'adventure couple'.

Listen Gugu Zulu's last interview with Radio 702's Sam Cowen