The money-spinning move comes nine years after he was released by Chelsea at the age of 15.
Arsenal and West Ham agreed a deal for the England midfielder this week after Manchester City pulled out of the race.
Rice will become the Gunners' second signing of the second after Kai Havertz completed a £65m move from Chelsea on Wednesday.
Rice was linked with a sensational return to Stamford Bridge in 2021 but opted to remain at West Ham who provided him with a platform to develop.
The 24-year-old has since gone on to become one of the Premier League's top performing midfielders - a far cry from his time at Chelsea's academy.
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Rice was released from Chelsea in 2014 and his difficult exit could have played a part in his decision not to return to the club two years ago.
According to The Athletic, Rice was released for three reasons. Among those cited was a lack of physicality.
Although fully aware of this particular flaw, Rice previously described himself as 'bambi on ice' and despite a growth spurt that followed, Rice was subsequently let go.
Rice's versatility appeared counterproductive in earning him a shot at Stamford Bridge.
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He has operated in both defensive and attacking midfield roles at West Ham and has even filled in at centre back on occasion.
But his time at Chelsea saw him deployed in a multitude of positions, including out wide which is likely to have impacted his future at the club.
The report also suggests Chelsea's acquisition of Sweden Under-16 defender Joseph Colley from Brommapojkarna impacted Rice's departure.
But time has passed, lessons have been learned and Rice is primed to make the step up with Arsenal appearing to be the right fit for the England man.
Mikel Arteta's side have been in dire need of a midfielder that fits Rice's profile and with Granit Xhaka and Thomas Partey set to move on this summer, Gunners fans could see a revamped midfield on show next season.
Arsenal will hope Rice's European heroics with West Ham earlier this month can help inspire the Gunners to success after narrowly missing out on Premier League glory.
And Rice will get his first taste of Champions League football, something a move back to Chelsea would have deprived him of next season.