The 26-year-old has agreed a four-and-a-half-year contract with Villa.

Sanson has played with Marseille since he signed for the club from fellow Ligue 1 side Montpellier in January 2017.

He was part of the Marseille team which made the Europa League final in 2018 and the one which finished second under Andre Villas-Boas last season.

Villa boss Dean Smith, whose team have had a strong first half to the Premier League season, was enthusiastic about Sanson's credentials after the deal was confirmed on Wednesday (AEDT).

"Morgan has performed consistently at the highest level in French football for a number of seasons as well as in this season's Champions League," Smith said.

"He is a player with the quality and experience to play in any midfield position.

"He will add real competition for starting places and gives us more squad depth which is vital to competing successfully in the Premier League."

Sanson has two goals and three assists in 10 Ligue 1 starts and two substitute appearances this season.

In his first interview with Villa, he told the club's website: "I'm really happy to be here, very proud to join the Aston Villa family.

"In the future I hope we can do great things together.

"It's a magical club, a big club in England. When Aston Villa called me, I didn't have to think about it for a long time – it was the best opportunity for me and my career.

"I love the team; I love the spirit – I'm a warrior and I like it when all the players run for the team and run for the club. I appreciate watching Villa because it's good football.

"I hope the best for the club. I think we have a very good team."

Villa is eighth in the table, just five points behind fourth-placed Liverpool with two games in hand on the reigning Premier League champion.

Having beaten Newcastle United last time out, it returns to action away to Burnley in the top flight on Thursday (AEDT).