The 22-year-old Belgium star has now agreed terms on a long-term contract and is expected to undergo a medical later this week.
Onana, if signed, will be the most expensive signing in Aston Villa's history, eclipsing Moussa Diaby who only joined last summer from German side Bayer Leverkusen for an initial £43 million.
This would be the club’s third midfield signing of the summer after Enzo Barrenechea and Ross Barkley joined the club in recent weeks. Winger Lewis Dobbin also joined from Everton for a £9 million fee last month.
The club have also brought back winger Jaden Philogene who is set to complete his return from Hull for £13.5 million over the next few days.
This Onana deal will take Villa’s spending for the summer window so far close to the £140 million mark.