Berger: Toro Rosso was impulse decision

The former Grand Prix driver has been a friend of Mateschitz for several years and, although he had been previously reluctant to accept an invite to help Red Bull's F1 activities, he has claimed it all changed during a conversation in Salzburg.

"Everything happened in one night, even though Dietrich and I have known each other for 20 years, when I was the first sportsman endorsing Red Bull," Berger was quoted as saying in Gazzetta dello Sport.

"Lately we've met fairly often in Salzburg and one evening, while chatting about the things we did together in the past and about future projects, all of a sudden he told me: 'I'd like to buy 50% of your company.' I thought he was joking, so I replied: 'Fine, then I'm buying 50% of Toro Rosso.' And we did it for real... "

Part of the deal that sees Berger buy into Toro Rosso is for Red Bull to buy 50 percent of Berger's shipping company.

Berger has made it clear that he is not becoming the team boss of Toro Rosso and says he is happy to leave responsibility of that role to fellow Austrian Franz Tost.

"Don't confuse me with the team boss," he explained. "That role is and will be Franz Tost's, a person I trust with my eyes closed.

"My long experience in F1, with all the things learned over the years, will be the contribution I'll bring to the team when I'll be asked.

"I can't miss [attending] the first Grand Prix. As for the others, we'll see one by one."