For much of that time, Mercedes junior and F2 driver Antonelli has been rumoured to be tasked with filling Hamilton's enormous shoes at the team, and now it is official.
Hamilton will be racing against the 18-year-old in 2025, but has sent his replacement a message before he does so.
Hamilton has had no involvement in the search for his replacement, though has regularly vocalised his support for the idea that Mercedes should recruit Antonelli.
Hamilton's rookie year in F1 saw him thrust into a team competing for wins, and he picked up four victories in his debut season with McLaren.
Should Mercedes continue their upturn in form - the W15 has three wins to its name in the previous six races - Antonelli could find himself in a similar position.
However, whereas Hamilton replaced Pedro de la Rosa and partnered reigning double world champion Fernando Alonso, Antonelli will line-up alongside an easier - though still a stern - test in George Russell.
On his Instagram story, Hamilton offered his well wishes to the young Italian, and predicted him to be a worthy addition at Mercedes from 2025.
"Congrats @kimi.antonelli. I have no doubt that you’ll bring a lot to the team alongside George next year 👏🏾,” he wrote.
Antonelli made his F1 debut with Mercedes in FP1 at the Italian Grand Prix, though his session came to an untimely end after just 10 minutes when he hit the barrier.
That did not affect his standing with team principal Toto Wolff, who confirmed the 2025 line-up one day later.