Alonso and Honda will re-unite in F1 from 2026 now that the two-time world champion has signed a contract extension with Aston Martin.
It marks a renewal of a partnership that triggered a great deal of frustration when they were at McLaren together from 2015 to 2017, as Honda's engines proved to be uncompetitive.
The partnership reached a public nadir at the 2015 Japanese Grand Prix when Alonso famously came on team radio and labelled the Honda a 'GP2 engine.'
The troubled relationship had prompted some doubts about whether Alonso and Honda could work together again, but that debate has now been put to bed with their future in F1 sorted.
And Honda Racing Corporation president Koji Watanabe has now explained that his company's relationship with Alonso has moved on greatly.
Speaking exclusively to Motorsport.com about working with Alonso again following the harsh comments he made in the McLaren era, Watanabe said: "When I worked with him from 2015 to 2017, it was a very difficult situation for both Honda and the team.
"It was a particularly frustrating period in our history, and there were times when our relationship was strained.
"But, I think we have become stronger because we overcame that frustration. Alonso has also been very active since then.
"I'm glad that we can overcome that painful experience together and fight together for victory once again. I hope that we can aim for the championship together and win together."
Watanabe has revealed that he began talking to Alonso again at the end of last year, with Honda's 2026 deal with Aston Martin having made it possible they could end up working together again.
"I spoke with him in Las Vegas," he said. "At the time, he hadn't decided on his next contract yet.
"But Alonso came when we were talking with [team principal] Mike Krack. He said: 'Good luck' and 'If we have a chance, let's race together.' We just spoke a few words."
Alonso's troubled history with Honda had not been ignored by Aston Martin as it concluded negotiations to become the Japanese manufacturers' works partner from 2026.
But following discussions about whether there would be any problem in him staying on board for the new era, Honda made it clear that it was delighted to have him.
"We had many conversations with Aston Martin regarding our partnership starting in 2026," added Watanabe.
"During that time, we exchanged opinions about drivers too and we shared an understanding between us and Aston Martin that Alonso was definitely a top-class driver.
"Aston Martin asked us if there would be any problems from Honda if they extended Alonso's contract. The situation was shared at various stages.
"But Honda did not make any requests regarding this matter. In any case, we should naturally discuss what kind of driver line-up we need to win, and it was in this context that the team decided to extend Alonso's contract."
