Sergio Perez has revealed that initial talks with McLaren started a few weeks ago - even though he denied at the time that he had been approached.
And although it appeared that Perez's McLaren move happened quite quickly, the Sauber driver says that discussions with his new bosses had been ongoing for some time.
"There have been talks before but I didn't want to give too much information away [at the time] about my opportunities and options," he said ahead of the Japanese Grand Prix. "The question didn't come up that often but if it did come up then there would be too many questions.
"So I am thankful the [McLaren] team gave me this opportunity. I want to leave this team [Sauber] on a high."
Perez says that his future was discussed with Ferrari too, but in the end there was no real opportunity for him.
"It was never clear with them if they wanted me or not," he explained. "It was difficult for them to make a decision and I think they are happy with Felipe [Massa]. He is a good driver and a proven driver.
"I am not a guarantee like Felipe, which is why I was never an option for them. The opportunity never came..."
Perez is under no illusions about the challenges he faces in stepping up to a title-winning team like McLaren, but has no doubts he is ready.
When asked about his feelings of being Hamilton's replacement, he said: "Of course I rate Lewis as one of the fastest drivers on the grid so it will not be easy at all.
"I know he has very big shoes to fill, and I will work as hard as possible to give the best results and win the championship with this great team."
He added: "I think with McLaren there is no other option - you have to win every race, if you have a car to win. I have to work very hard, give everything to my team and I am ready to do it once I finish the season."