Three-time Formula 1 world champion Niki Lauda is recovering in hospital after undergoing a lung transplant. The Austrian great was reported to have recently cut short a holiday after falling ill, and he had not been present at the past two grands prix with Mercedes.
The Silver Arrows' non-executive chairman was missing at Hockenheim and the Hungaroring, with Austrian media reporting that he had fallen ill in Ibiza and required hospital treatment upon returning to Austria.
"Because of a severe lung condition Niki Lauda had to undergo a lung transplant in Vienna General Hospital," the hospital said in a statement. "The transplant was carried out successfully."
Lauda won three drivers' titles in his career in 1975, 1977 and 1984.
His famous duel with James Hunt in the mid-seventies is regarded as one of F1's all-time great rivalries.
Lauda suffered a near-fatal crash during the 1976 German Grand Prix at the Nurburgring, crashing into an embankment, which set his car up in flames, before two drivers crashed into the wreckage.
After being rushed to hospital, it was confirmed Lauda suffered severe burns, but he returned to racing just six weeks later and won his second championship the following year.
Having retired for a second time in 1985, Lauda became an aviation entrepreneur, founding Lauda Air, while also serving as a consultant for Ferrari and team manager at Jaguar.
Since 2012 he has been non-executive chairman of the Mercedes team, which he owns a 10% share in.
Lauda was key to the Silver Arrows signing Lewis Hamilton in 2013, personally handling the negotiations with the Briton, who has won three world titles with the team and tops the standings by 24 points with eight races remaining in 2018.