F1's driver shake-up likely to see Hamilton remain at Mercedes
Hamilton's future had been slightly cloudy, with a deal not yet in place at Mercedes beyond the end of the 2020 season.
Sebastian Vettel's announcement at the beginning of the week that he was leaving Ferrari led some to wonder whether Hamilton could make a switch to Maranello, which had been touted last year.
However, Ferrari announced on Thursday morning they had signed Carlos Sainz Jnr from McLaren to partner Charles Leclerc and replace the out-going four-time world champion Vettel.
Ferrari team principal Mattia Binotto said: "We believe that a driver pairing with the talent and personality of Charles and Carlos, the youngest in the past 50 years of the Scuderia, will be the best possible combination to help us reach the goals we have set ourselves."
And McLaren reacted in kind, confirming seven-time race winner Daniel Ricciardo would partner Lando Norris for the 2021 season.
That leaves a vacant spot at Renault, but with the team finishing fifth in the standings last season, it leaves Hamilton with little option for a front-running team other than to re-sign with the Brackley team who have guided him to five of his six world championships.