"If you had told me when I started in 1994 that I would retire after 15 seasons, I would have bought that, " Coulthard told BBC Radio 5 Live.

BBC: Coulthard announces F1 retirement

"If you'd told me when I started this job that my largest financial supporter, philanthropic supporter, was going to be Bill Gates, I would have told you, 'You're kidding me, ' " Klein says.

FORBES: Legal Adversary Turned Ally