The car is set to be title-sponsored by the iconic Italian drinks brand Martini, raced by the long-time Ferrari driver Felipe Massa, and this week it emerged that Brazilian oil sponsor Petrobras has returned to the team.
Now, the next piece in the puzzle is believed to be GP2 frontrunner Felipe Nasr, whose surname oddly rhymes with that of his Brazilian countryman Massa.
We reported recently that the 21-year-old is believed to have signed an agreement to be Williams' reserve driver in 2014, including Friday practice running at about half of the 19 grands prix.
And Germany's Speed Week now reports that Nasr will bring about EUR 10 million to Williams in the form of his sponsor Banco do Brasil, a major Brazilian bank.
When the Petrobras deal was unveiled in Rio this week, deputy team boss Claire Williams would not confirm the Nasr deal.
"I can't comment on that," she is quoted by Globo, "but for Brazil I'm sure it would be awesome.
"Formula one is a big market for Brazil; the people love sports and formula one in particular.
"So I guess to have another Brazilian in F1 along with Massa would be good for the sport and good for Brazil," Williams added.