Ferrari great Michael Schumacher has signed a special helmet to be worn by fellow Formula 1 champion Jackie Stewart during a tribute lap of the Bahrain Grand Prix circuit on Sunday to raise funds for dementia research.
Schumacher, now 56, has not been seen in public since the seven-time world champion German suffered a serious brain injury in an accident while skiing in the French Alps in December 2013.
Organisers said all 20 living Formula 1 world champions had signed the helmet that triple champion Stewart, 85, will use while driving his 1973 title-winning Tyrrell on the 60th anniversary of his Formula 1 debut.
"It is wonderful that Michael could sign the helmet in this worthy cause, a disease for which there is no cure," Stewart told the Daily Mail newspaper at the Sakhir circuit.
"His wife [Corinna] helped him, and it completed the set of every single champion still with us."
The newspaper reported that Schumacher had been helped to write the initials MS on the white helmet featuring the Stewart tartan that the Scot wore while racing in the 1960s and 70s.
A spokeswoman for the Schumacher family confirmed to Reuters the details were correct.
Stewart set up the charity Race Against Dementia in 2016 after his wife Helen started to suffer from the disease.
The charity raises and allocates funds to accelerate global research, in keeping with Formula 1's rapid response to problems, to prevent and treat dementia.