Michael Schumacher has been inundated with goodwill wishes on his 50th birthday.
The seven-time F1 champion suffered serious head injuries in a freak skiing accident on December 29, 2013 and his family remain fiercely protective about revealing details about his physical state. He continues to receive specialist treatment at his home in Switzerland.
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Social media was awash with birthday messages on Thursday, led by current world champion Lewis Hamilton who posted a tweet to his "inspiration."
"Wishing you a happy birthday, Michael. 50 years of life and a legacy that will last forever. What an honour it is to say that I have raced with you.
"You've always been a true inspiration to me and the entire world. Keep fighting, Champ," the Mercedes driver wrote.
Schumacher became synonymous with Ferrari during his illustrious career, winning five successive world titles between 2000-2004.
His former team tweeted a message of support to its "champ."
After a temporary retirement in 2006, Schumacher returned four years later to drive for Hamilton's current team, Mercedes.
"50 years ago, a star was born. A star who shaped and changed F1 forever. Who broke records, redefined excellence and helped lay the foundations for our future success," tweeted the Mercedes team.
"We'd like to send our very best wishes to Michael on his 50th birthday."
Current Ferrari driver Sebastian Vettel, who has won four world titles, shared a picture on Instagram of him as a child posing with Schumacher.
FIA president Jean Todt tweeted: "Affectionate thoughts for Michael @schumacher , the greatest @F1 champion in history, with unbroken records."
An official Schumacher app -- which will be a "virtual museum" of the driver's achievements -- has been released to honor the driver who secured a record seven championships and 91 race victories.
"We are very happy to celebrate Michael's 50th birthday together with you and thank you from the bottom of our hearts that we can do this together. As a gift to him, you and us, Keep Fighting Foundation has created a virtual museum," said the statement.
"The app is another milestone in our effort to do justice to him and you, his fans, by celebrating his accomplishments."