Samir Nasri has won a six-month deal with West Ham United.
The former Arsenal and Manchester City midfielder has been training with the Premier League club since early November.
And having been handed the No.18 shirt, the Frenchman could make his debut against Brighton on Wednesday.
Nasri has now served his 18-month doping ban and has proven his fitness to Hammers boss Manuel Pellegrini.
The 31-year-old worked with the Chilean at City and said: “You choose a club and a project because of the ambition, and I think that West Ham has everything to be one of the biggest clubs in London.
“We play in the Olympic Stadium, the training ground is there and you have owners who wants to invest and have a good team. Everything is there to be doing great things.
“Coming back to the most competitive league in the world, with a team full of ambition with a manager that I know; it’s the best job in the world, and I’m really excited about it.”