Ever since Sauber has been running teaser 'Out of the blue' and 'True blue' graphics on its engine cover livery in China and Bahrain, speculation about the identity of the forthcoming sponsor have been swirling in the F1 paddock.
We reported the rumor that the deal could be with the Russian billionaire Roman Abramovich, to promote his football club Chelsea.
Swiss F1 team Sauber confirmed the "new and innovative partnership" on Monday.
"The C31 sporting the blue logo of Chelsea FC will be seen for the first time at the Spanish grand prix," the Hinwil based team announced in a media statement.
"A partnership like this between formula one and football has never existed before in this form, yet there are numerous commonalities and possible synergies," said Sauber chief executive Monisha Kaltenborn.
The statement said Chelsea will in turn display Sauber's logo on its advertising boards and interview walls, ensuring one another "a significant market presence outside their original sport".
04/19/12 (GMM) Sauber's 'teaser' has done the trick, triggering paddock speculation about its forthcoming major backer.
Last weekend in China, off the back of Sergio Perez's recent push for victory at Sepang, the small Swiss team ran mysterious 'Out of the blue' signage on the C31's engine cover.
The Blick newspaper said it was a "teaser" for a "big sponsor" that will be "announced in a few weeks".
So who is it?
Germany's Auto Motor und Sport relayed paddock rumors hinting that the deal could be with AT-T, the American multinational who last year pulled its title sponsorship of the then-struggling Williams team.
Another paddock whisper is that Sauber's new deal could be with the Russian billionaire Roman Abramovich, to promote his English premier league club Chelsea.