Adidas was already 24-year-old Wilkinson's main sponsor, but his previous deal with the sportswear firm was estimated to be worth around £250,000.
Adidas' sponsorship has paid off superbly for the firm, with the fly half scoring the winning drop goal of the Rugby World Cup final against Australia with only seconds to spare, and being named by the International Rugby Players' Association as the player of the year.
Adidas will now use Wilkinson as a standalone star to front future advertising campaigns, which will be created by Adidas agency Amsterdam 180.
Earlier this year, Wilkinson appeared alongside David Beckham in an amusing rugby meets football spot by 180 where the two exchanged kicking tips.
During the shoot, it turned out that Wilko and Becks really were good at each other's sports, with Beckham nailing every penalty kick he attempted with the rugby ball and Wilkinson learning Beckham's famous ball-bending trick to score goals at will.
Despite an overwhelming number of offers, Wilkinson's agent has said that the star will only sign endorsement deals that fit into his rugby schedule.
The £2m Adidas agreement is sure to be followed by several other key sponsorships, with pundits suggesting Wilkinson could bank deals worth a total of £5m.
Earlier this year, Wilkinson agreed a deal with Lucozade Sport to star in its advertising and for upmarket casualwear brand Hackett.
Immediately after the Rugby World Cup, Adidas ran tactical press ads featuring Wilkinson to celebrate England's victory over Australia.
The ads showed Wilkinson lining up balls to hone his goal-kicking talent, with the line: "Monday, back to work".
They played on the fact that Wilkinson practices for several hours every day -- although he restricts himself to only an hour's practice on Christmas Day, it is reported.
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