The agreement will see the Movistar Yamaha rider become the face of the brand for 2014 and the 26-year-old will sport their logo on both his racing suit and helmet for the upcoming MotoGP season.
Lorenzo, the only Spaniard to have claimed two world titles in the premier motorcycling class - in 2010 and 2012 - lost out to compatriot Mark Marquez last season.
But, riding his Yamaha YZR-M1, Lorenzo will look to get back on top as the new season fires up this weekend with the Qatar Grand Prix in Doha.
When not racing competitively during 2014, Lorenzo will have a chance to drive the Alfa Romeo 4C supercar as part of the deal.
Alfa currently provide the safety car for the World Superbike championship and Lorenzo will be charged with taking the car onto the track at some races during the season.
Lorenzo and his staff will also be given use of Giuliettas, including the new Quadrifoglio Verdes, during race weekends.
The agreement between the Alfa Romeo and Lorenzo also includes communication and marketing activities on the traditional channels, the web and social media over the course of 2014.
- Sports & Recreation
- Alfa Romeo