Barkley completed his move to Villa Park on Wednesday morning where he was unveiled following his short-term move from the Blues.
The 26-year-old has scored 25 goals in 202 Premier League appearances across spells with Everton and Chelsea and boasts 33 England caps to his name.
He becomes Villa's fifth signing of the season following the arrivals of Ollie Watkins, Bertrand Traore, Emiliano Martinez and Matty Cash.
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9. Nathan Ake - Bournemouth to Manchester City (€45.3million)
8. Mauro Icardi - Inter Milan to Paris Saint-Germain (€50million)
7. Ben Chilwell - Leicester City to Chelsea (€50million)
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