This also marks the first time a Yamaha MotoGP rider has worn the #1 since Wayne Rainey defended his World Championship title in 1993 for the third consecutive time.
The #1 plate was already used in racing when he did his first official test at Valencia circuit in the end of last year.
"Today I can reveal my No 1," said Jorge Lorenzo. "I am very proud because you have to work very hard to have the option to wear it. I have been lucky with my design because the No 1 works really well with my JL initials, maybe with different letters it would have been difficult to make it look right, I hope my fans will like it!"
"I won't forget my No 99 this season, it will be there somewhere on my leathers because No 99 is in my heart. It was a difficult choice to change my number but I have earned the right for this unique opportunity to wear it," Lorenzo concluded.
The #1 plate was absent from MotoGP from 2001-2005, when champion Valentino Rossi chose to retain his famous #46. The last time a MotoGP champion used the #1 was Casey Stoner in 2008. The last time a 500cc/MotoGP rider successfully defended his title while wearing the #1 was back in 1998 with Mick Doohan (Honda).