Lewis Hamilton has revealed he made the "hardest decision" of his life to put his 12-year-old bulldog Roscoe to sleep.
The British former world champion missed a Formula One tyre test in Italy on Friday to be with his sick pet, who had been hospitalised with pneumonia.
The 40-year-old Ferrari driver said Roscoe had died in his arms on Sunday.
"After four days on life support, fighting with every bit of strength he had, I had to make the hardest decision of my life and say goodbye to Roscoe. He never stopped fighting, right until the very end," Hamilton wrote on Instagram.
"I feel so grateful and honoured to have shared my life with such a beautiful soul, an angel and true friend. Bringing Roscoe into my life was the best decision I ever made, and I will forever cherish the memories we created together.
"It is one of the most painful experiences, and I feel a deep connection to everyone who has gone through the loss of a beloved pet."
Roscoe has been a regular feature in the F1 paddock and at major events such as awards ceremonies since the seven-time world champion adopted him in 2013.
Hamilton is set to be back in action at this weekend's Singapore Grand Prix.