Yamaha have kicked off their 50th anniversary celebrations with a rare appearance from a number of the manufacturers Grand Prix riders, past and present, at Laguna Seca on Thursday.

Yamaha Factory Racing's Jorge Lorenzo and Ben Spies along with Monster Yamaha Tech 3's Colin Edwards and Cal Crutchlow were joined by living GP legends Kenny Roberts Sr, Eddie Lawson, Wayne Rainey and Kel Carruthers in a special presentation.

The event saw the MotoGP legends reveal their most memorable moments in Yamaha colours after spending the early part of this week making a tongue-in-cheek video entitled 'A Blast From the Past' which can be viewed here.

Later today, “The King” will take to the track on a one-off Yamaha YZF R1 sporting the 50thAnniversary red and white colour scheme which Lorenzo and Spies will compete in this weekend. Saturday will see him repeat his track tour, but this time on the YZR-M1 before his grand finale on Sunday on track with his 1979 Yamaha 500cc GP bike.

The real on-track action begins at 18:10 UK time this evening with first practice for the Red Bull U.S. Grand Prix as Lorenzo and Spies look to mark the 50th anniversary of the Japanese manufacturer's Grand Prix debut with victory at Laguna Seca.