West Ham United FC (@whufc_official) August 30, 2014
Song, 26, made his name with Arsenal after joining from French side Bastia in 2005, but after a superb 2011-12 season, the Cameroon international left London for a move to Barcelona. However, having failed to play ahead of first choice defensive midfielder Sergio Busquets, Song is back in London with West Ham - despite reported interest from Tottenham Hotspur.
Manchester United and even Arsenal had been linked with a move for Song before the World Cup, but his immature display against Croatia no doubt costed him having been sent off for elbowing striker Mario Mandzukic off the ball.
Yet Sam Allardyce is seemingly happy to have landed Song to improve his midfield, with Song even says that he turned down offers from Champions League clubs in order to return to the Premier League.
"I'm very happy to be here and very happy to see the guys and the fans today and to start to do my job for West Ham United," said Song. "I think this is very important for me to be coming back to London to West Ham United, which is a club with ambition to build a new stadium and become a big club. I am very excited to be part of this project."
"For me, when I was in Spain, I always said that if I was to leave one day I would return to the Premier League. It was a very hard decision, because when you have options of a lot of clubs who are playing in the Champions League, but at the end of the day I chose West Ham because I wanted to come to the Premier League. This is a league which has given me a lot and I didn't finish what I wanted to achieve here.
"For my family too, it was very important, because my children and my wife wanted to come back to England. This is an opportunity to do that with West Ham and I just took it. I am very happy to be here and very proud to be part of the project at this club," he added.
Is Song a good signing for West Ham?