Alpine boss Otmar Szafnauer says he discovered Fernando Alonso's Aston Martin move via press release

Alpine team principal Otmar Szafnauer says he only found out about Fernando Alonso's move to Aston Martin when he read the official press release.

Two-time Formula 1 world champion Alonso, 41, penned a multi-year deal with Aston Martin on Monday and will move to the team at the end of the season following Sebastian Vettel's retirement.

Szafnauer was confident of tying the Spaniard down to a new deal, saying his team had guaranteed Alonso a seat for 2023 with an option to extend for another year.

• Fernando Alonso to join Aston Martin as Vettel's replacement
• Why Aston Martin? What triggered Fernando Alonso's move?

Szafnauer told reporters on a Zoom call: "Obviously when we're in the paddock, there's all sorts of rumours, and I had heard rumours that Aston were interested [but] it was the first confirmation I had.

"Once you hear that they're interested, there's probably discussions that took place. I was confident that, even with the discussions, and there's nothing wrong with exploring, that we were very close [to a new deal].

"So yes, the first confirmation I had was the press release. I did ask the question (to Alonso). And I was told: 'No, no, I haven't signed anything'. So I was a bit surprised.

"We offered a one plus one deal. And we discussed with Fernando that: 'Look, if next year at this time you're performing at the same level, of course, we will take you and that could have carried on'. But I think he wanted more certainty independent of performance."

Ted Kravitz analyses Alonso's move to Aston Martin

Sky Sports F1's Ted Kravitz reacts to the out-of-the-blue announcement that Alonso is swapping Alpine for Aston Martin.

Kravitz said: "Obviously Fernando is out of contract and has been looking around the big teams. He admitted when I spoke to him before the Spanish Grand Prix that he would be happy to go to any big team and be a number two to Charles Leclerc or Max Verstappen.

"So his mind was clearly not with staying at Alpine. Or at best, staying at Alpine would be a second choice to joining a big team. So in those terms, maybe it's not entirely unexpected that he was thinking of a move."

"For Alonso, if his mind is not to stay at Alpine, and with other avenues closed, he might be looking at what Aston Martin are building up.

"They've got a lot of people in from Red Bull, Dan Fallows, for example, has arrived as technical director and has started coming to races, and Alonso will know about him and others. He will also know there is money there and he thought this was the best option. But what does this say about Alpine?"

Martin Brundle dissects Alonso's decision

Sky Sports F1's Martin Brundle...

"It appears that Alpine couldn't or wouldn't offer Alonso a two-year deal, and his Aston Martin deal is officially described as multi-year.

"He's also been fairly underwhelmed at how punchy his team-mate Esteban Ocon has been towards him in combat at Alpine rather than turning all their guns on their rivals.

"Fernando is a force of nature on and off the track and he will push the team very hard. He's mellowed a little these days but there could easily be fireworks as he joins the Stroll family 'firm'.

"I remember interviewing Fernando on the 2018 Abu Dhabi grid and he was very convincing that it really was the end of his F1 career, but now he'll be on the grid until at least the end of 2024 at the age of 43 and with 400 F1 races under his right foot. Extraordinary."