Now in Bahrain, the logo of Bahrain flag carrier Gulf Air is on the car, triggering the obvious conclusion McLaren might continue its new policy of livery changes throughout the 2014 season.
A spokesman would not comment "on future liveries".
But Sky News reports that McLaren is in title sponsor talks with a Japanese giant called Rakuten, owner of the well-known UK retailer play.com.
The report said the deal could be worth more than $60 million per year to the Woking based team, but a spokesman said: "McLaren never comments on unsubstantiated rumours of this kind."
Meanwhile, the Spanish sports daily Marca has made a link between McLaren and the former F1 sponsor Movistar, a Spanish mobile phone operator.
The rumour seems to have been triggered in part by an official McLaren 'tweet' on Friday featuring a photo of Ron Dennis sitting in the Bahrain paddock with Fernando Alonso in 2007.
The caption said it was "Another pic of Ron smiling".
A McLaren source strenuously played down the significance of the tweet.
But it does follow hot on the heels not only of Dennis' return to the team, but also rumours last year that Alonso could be wooed back to McLaren for the impending Honda era.
The Alonso camp immediately played down the connection.
"Fernando is happy where he is" at Ferrari, his manager Luis Garcia Abad insisted.
But Alonso was not totally unequivocal when asked by Spain's Diario AS if there is "any chance" he will leave Ferrari at the end of the year.
"No, I think not," said the double world champion, who admitted he arrived at the great Maranello team in 2010 expecting to win a title.
"When I came to Ferrari I won my first race here and I thought I would win the championship in that year or another year. Definitely," he said.
"That was the recent history of Ferrari, in 2010 Ferrari was very strong, I came, I won the first race, everything seemed to be in the right direction."
Despite yet another season having begun in which a third title for Alonso appears unlikely, the driver insists he does not regret joining Ferrari.
"No, there are many decisions in your career and your life that you make and that's it.
"You never know what would have happened if I had accepted offers from Red Bull or Toyota or whoever," he added.