Pires helped France win the 1998 World Cup and 2000 European Championship as well as winning two Premier League titles and three FA Cups with Arsenal.
Villa's assistant boss Gary McAllister confirmed: "I believe he's going to join us in the next two to three days."
Pires, who spent six years with the Gunners and was voted their sixth greatest player of all time in an online poll, has been training with his former manager Arsene Wenger at Arsenal's training ground in recent weeks.
I just hope he doesn't play against us in a few weeks. Most of our former players seem to score against us
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His arrival at Villa Park will be a boost for manager Gerard Houllier's squad which has been depleted by injuries to the likes of John Carew, Emile Heskey, Stiliyan Petrov, Nigel Reo-Coker and Steve Sidwell this month.
McAllister added: "I know the [Villa] boss [Houllier] and Arsene Wenger are very friendly.
"It's perfect. I am sure he will arrive at the training ground in good condition.
"He's a player everyone can look up to because of what he has achieved."
Source: BBC Sport