The France international winger has moved to the Hammers from Ligue 1 outfit Marseille, as announced on the Premier League club’s official website last week.
Payet has signed a five-year contract with a further one-year option for an undisclosed eight-figure fee.
“He was one of the most creative wingers in the major European Leagues last season and I think it is an unbelievable signing,” Sullivan wrote on West Ham’s official website.
“I cannot wait to see him in action. He has everything to his game – pace, flair, can pass the ball and will add even more creativity to our team.
“We have paid a hefty price for him and it shows the ambition and intent that the Club have got now.”
Good signing for West Ham United
The signing of Payet from French giants Marseille is a statement of intent from West Ham.
Payet’s arrival at West Ham shows that the club are determined to be successful in the coming years and how serious they are about competing with the big teams.
The Frenchman was one of the best players in Ligue 1 last season, helping Marseille finish fourth in the league table.
The former Lille star scored seven goals and created 134 chances in 36 league appearances.
The 28-year-old had a pass accuracy of 80% and a shot accuracy of 47%, and won three headers, 66 dribbles and 17 tackles.
Signing Payet shows that West Ham must be taken seriously next season. The London outfit are still looking for players to sign this summer, which suggests that they are bent on finishing in the top eight or the top six in the Premier League during the 2015-16 campaign.
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