As part of the new deal, Hamleys logo will feature on the sidepod positions of the Williams’ car. The retailer’s brand will also feature within the team’s environment.
Hamleys has partnered with the team since the 2004 season.
Team principal, Frank Williams said: "Hamleys has been an enduring partner for AT&T Williams and we are genuinely delighted that today's increased sponsorship commitment has been prompted by our successful relationship to date.
"Increased support from premium brands such as Hamleys will give our partner portfolio an invaluable international retail presence."