* Alfa Romeo return to F1 after 30-year break
* Italian brand to be Sauber's title sponsor
* Swiss team will be renamed Alfa Romeo Sauber
* Drivers yet to be confirmed
* Sauber will continue to use Ferrari engines (Adds background)
By Alan Baldwin
LONDON, Nov 29 (Reuters) - Alfa Romeo are returning to Formula One for the first time in 30 years with the century-old Italian marque partnering the Swiss-based Sauber team as title sponsors.
The team's official name from next season will become Alfa Romeo Sauber F1 as part of a multi-year technical and commercial partnership, with the Ferrari-powered cars sporting Alfa's colours and logo.
"This agreement with the Sauber F1 Team is a significant step in the reshaping of the Alfa Romeo brand," Fiat Chrysler chief executive Sergio Marchionne said in a statement on Wednesday.
The move, which had been widely expected, comes after the end of a Formula One season that saw Ferrari finish runners-up to Mercedes in the constructors' championship while Sauber were last.
Ferrari’s late founder Enzo started out racing and managing a team for Alfa Romeo, before setting up on his own in the late 1930s. Ferrari celebrated the 70th anniversary of his first car this year.
The first two Formula One world championships in 1950 and 1951 were won by Italian Giuseppe ‘Nino’ Farina and Argentine Juan Manuel Fangio in Alfa Romeo cars. The constructors' championship did not start until 1958.
The company, founded in 1910, supplied engines in the 1960s and 1970s and returned as a constructor in 1979 before again withdrawing at the end of 1985.
Italian car giant Fiat bought Alfa, whose iconic red Spider 1600 model was driven by Dustin Hoffman in the 1967 cult film "The Graduate", in 1986 and Alfa branding has featured on Ferrari Formula One cars in recent seasons.
"Working closely with a car manufacturer is a great opportunity for the Sauber Group to further develop its technology and engineering projects," said Sauber Holding AG chairman Pascal Picci.
"We are confident that together we can bring the Alfa Romeo Sauber F1 Team great success, and look forward to a long and successful partnership."
The team have yet to announce their 2018 driver lineup but Ferrari-backed Formula Two champion Charles Leclerc is expected to be one of them.
Italian Antonio Giovinazzi, also a Ferrari contracted driver, could be the other, although Sweden's Marcus Ericsson has close ties to the team's backers and may stay despite failing to score a point this year.
Marchionne, who is also chairman of Ferrari, and Picci will present the new team at Alfa's museum in Arese, near Milan, on Saturday. (Reporting by Alan Baldwin; Editing by Christian Radnedge and Ken Ferris)