Ferrari junior driver Antonio Giovinazzi will race alongside Kimi Raikkonen at Sauber in 2019.
The Italian joins the team with backing from Ferrari and Sauber's title sponsor Alfa Romeo. The deal will see an all-new driver line-up for the Swiss team next year, with current driver Charles Leclerc set to replace Raikkonen at Ferrari next year and Marcus Ericsson, who has been at Sauber since 2015, due to take on a reserve driver and brand ambassador role.
Giovinazzi raced for Sauber in 2017 when he replaced the injured Pascal Wehrlein at the Australian and Chinese Grands Prix, and he has tested for both Sauber and Ferrari this year.
"We are very pleased to reveal the complete driver line-up for the 2019 season," Sauber team principal Frederic Vasseur said. "We first signed Kimi Raikkonen, 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."
Giovinazzi added: "I am delighted to be joining the Alfa Romeo Sauber F1 Team. This is a dream come true, and it is a great pleasure to have the chance to race for this team. As an Italian, it is a huge honour for me to represent a brand as iconic and successful as Alfa Romeo in our sport.
"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."
Giovinazzi's role as a Ferrari reserve driver means his racing experience over the past two years has been limited. He took part in the 24 Hours of Le Mans this year in a Ferrari GT car, but other than the two grands prix as Wehrlein's replacement in 2017 has not raced in single seaters since finishing second to Pierre Gasly in the 2016 GP2 championship.
Prior to that, he raced in a mix of various series, including European and Asian LMS as well as Germany's DTM and European Formula 3.
In 2017, he became the first Italian to race in F1 since Jarno Trulli and Vitantonio Liuzzi took part in the 2011 season.