Ambrosio will be sharing exclusive moments at parties and cultural events across Cīrocs social media platforms.
Ambrosio's part in the campaign has kicked off with the release of a shot by photographer Mario Testino showing the model having her hair and make-up done before one such event.
Samantha Reader, global marketing director for Diageo Reserve, said: Cīroc On Arrival is all about celebrating moments of success and being at the forefront of whats hot, so were really excited to be working with Alessandra as one of the biggest talents of today.
Cīroc is for those who dream big, aspire to greatness and recognise the importance of celebrating success when it arrives.
Alessandra embodies this in everything she does, and were looking forward to celebrating with her this year.
Ambrosio added: I really do believe in celebrating life at every moment, and Im really looking forward to bringing Cīroc and my fans along on my journey and giving them behind-the-scenes access to the biggest moments of my year.