Williams on Tuesday finally confirmed long speculation the Brazilian oil company Petrobras will return as a sponsor in 2014.
It has been rumoured for some time that Petrobras, having backed the Grove outfit between 1998 and 2008, would be wooed back to Williams by the signing of Brazilian Felipe Massa.
The team announced the deal on Tuesday.
"Petrobras and Williams have had a successful partnership before and we are both looking forward to reuniting for 2014," said Sir Frank Williams.
A media statement said Williams' Mercedes-powered FW36 will feature Petrobras logos, while a new fuel will be developed for use in F1 in 2015.
"Technologically they are very strong and that will be important for the team as the new regulations have made fuel efficiency increasingly important," team founder and boss Williams added.