Giovinazzi made his F1 debut with Sauber at the 2017 Australian Grand Prix, finishing 12th, and competed at the Chinese GP that season but failed to finish. Alongside regular FP1 and test outings with Sauber and Haas, he has also tested for Ferrari.
“As an Italian, it is a huge honour for me to represent a brand as iconic and successful as Alfa Romeo in our sport,” said Giovinazzi.
“I would like to thank the Scuderia Ferrari and the Alfa Romeo Sauber F1 Team for giving me this great opportunity. I am very motivated and cannot wait to start working towards achieving great results together.”
Sauber CEO and team principal Frédéric Vasseur said: “We first signed Kimi Räikkönen, an extremely experienced driver who will contribute to the development of our car and will accelerate the progress of our team as a whole.
“Together with Alfa Romeo, we are delighted to welcome Antonio Giovinazzi, who will take the place of Charles Leclerc. We have already had the opportunity to work with him in the past and he has proven to have great potential. We are very determined and motivated.
“Our target is to continue progressing and fighting together for positions that count.”