Meanwhile, in terms of drivers, the Swiss team are retaining the services of Marcus Ericsson, but are replacing Pascal Wehrlein with the services of Charles Leclerc.
The line-up was announced at a special press event in Milan, Italy on Saturday, where the team revealed further details of their new title sponsorship deal with Alfa Romeo, including a revised red and white livery concept for next season's vehicle and a new logo. During the event, a previous generation F1 auto was unveiled featuring a red and white livery and a prominent Alfa Romeo badge (above, with Leclerc and Ericsson).
Giovinazzi will stay as the team's back-up driver and it remains to be seen if Wehrlein moves to Williams - the only remaining team with a vacancy.
Ferrari-backed Leclerc, from Monaco, had been expected to get the drive.
Fiat Chrysler have invested billions of euros since 2014 to develop new Alfa Romeo models that would stand up against German premium rivals and shed a reputation for poor quality and service that has hit sales in the past decade. He is clearly deserving of a shot in Formula One.
With Sauber teaming up with Alfa Romeo ahead of the 2018 championship, Leclerc was widely tipped to take one of the two Sauber race-seats.
Instead, the team will use Ferrari power elements badged with the iconic Alfa Romeo brand.
The 38-year-old Raikkonen signed a third straight one-year deal to remain with Ferrari through 2018, but a return in 2019 on a fourth consecutive one-year deal isn't overwhelmingly likely.
Alfa Romeo supplied engines in the 1960s and 1970s and returned as a constructor in 1979 before again withdrawing at the end of 1985.