The 41-time capped France international has joined West Ham United on an initial contract until the end of the 2018/19 season, with the option to extend his stay for one year - after proving his fitness levels over the past few weeks.
On the day an 18-month ban for a doping ban expired the 31-year-old penned his contract and is available to face Brighton in the Premier League tonight.
He previously played in England with Arsenal and Manchester City, winning two titles while at the Etihad, the second of which came under current Hammers manager Manuel Pellegrini in 2014.
"I'm really happy that West Ham and Manuel Pellegrini have given me a chance to be playing again," Nasri told West Ham TV.
"I know the manager really well. We won the Premier League title together and I'm really passionate about my job.
"Pellegrini was the biggest factor for me to be joining West Ham. When you're a player, you want the manager to know your quality and want you because he's the one that is going to be playing the team, and knows your quality.
"The guy is a genius. He thinks a lot about everything and he has that mentality about football, and we share the same mentality."
Nasri was handed an initial six-month ban which was later extended to 18 months but back-dated to July 2017 after he received an intravenous treatment at a Los Angeles clinic in breach of the World Anti-Doping Agency's rules.
And the talented midfielder who made 215 appearances in the Premier League, playing for The Gunners from 2008 to 2011 before moving to City for £25m - conceded that he felt it was the end of his professional football aspirations.
"I had some really tough moments when I was really down," he said. "Mentally I'm really strong, but for maybe the first time in my life, I cried about my career because I thought it was over.
"I'm 31 years old now and I'm more mature. If it was five years ago maybe I would have some problem with it or talk too much about it.
"When you've been out for a year and you think it's over, you think completely differently after that.
"I was just looking on TV and I wasn't able to train, and in the meantime, I had a son. A lot of things have changed in my life, and for the best. I'm really happy about it. I'm just blessed.
"I'm lucky to have a second chance. Not everyone in life has a second chance and I do. I know I will give 100 per cent."