Roma have made France international Steven N'Zonzi their 12th new signing this summer.
The World Cup winner landed in the Eternal City from Sevilla on Tuesday to undergo a medical, having already agreed personal terms with the Giallorossi, and was presented later in the evening.
"I'm very happy to be here and to be a Roma player," Nzonzi told Roma TV of the move. "I'm very pleased to be here.
"I really felt that the club wanted me to come. This is why I am here, and I'm happy to join such a big club."
Roma's sporting director Monchi raided his former club for a player he signed for them from Stoke City in 2015. Roma are reported to have agreed a fee of €32 million for the midfielder who had a release clause in his contract -- which still had two years left to run on it -- valued at €35m.
"Yes, Monchi signed me at Sevilla," N'Zonzi said. "He helped me a lot when I was there. We always had a lot of respect for each other and he helped me a lot at Sevilla, so I'm very happy to be here and work with him again.
"I'm very happy for the welcome that [the fans] gave me at the airport and the support they showed.
"I just want to say that I will give my best on the pitch and hopefully be a very good player for this team."
He is likely to be the last arrival of a very busy transfer window for Monchi, who has brought in Ante Coric, Ivan Marcano, Bryan Cristante, Justin Kluivert, Antonio Mirante, Davide Santon, Nicolo Zaniolo, William Bianda, Javier Pastore, Daniel Fuzato and Robin Olsen.
Alisson Becker, Radja Nainggolan and Bruno Peres have all left the club, who finished third behind Juventus and Napoli in Serie A last season and reached the semifinals of the Champions League, where they were beaten by Liverpool.
N'Zonzi, 29, featured in five of France's World Cup fixtures, including the final. He made 90 appearances in La Liga and played 195 times in the Premier League for Blackburn Rovers and Stoke.
He is expected to challenge club captain Daniele De Rossi for a place in Eusebio Di Francesco's midfield. Roma get their Serie A campaign underway on Sunday with a trip to Torino.