Everton have re-signed midfielder Idrissa Gueye from Paris St-Germain on a two-year deal for a fee of about £2m.
The Toffees had been in advanced talks over bringing the 32-year-old back to Goodison Park since the start of last month.
PSG signed Senegal international Gueye from Everton for about £30m in 2019.
Having made 108 appearances for Everton between 2016 and 2019, he said: "There is no better feeling than coming back home."
"I am very happy to be here at Everton again, to help and to work hard - I'll give my soul to this team," added Gana.
"Coming back here was important to me because I feel like I'm in my home. I've followed the team every week and watched how they play. For me, there is no better place than Everton, so that's why I chose to come back here.
"There is also a great atmosphere at the stadium and everyone here is like a family. I felt very, very good when I was here [the first time] and even when I went to Paris, I kept in touch with some of the players and continued to support the team.
"For me, it's special. I told PSG if I am going to leave, it will be for one team — and that was Everton."
Gana scored seven goals in 111 games for PSG, winning both Ligue 1 and the French Cup twice and helping them reach the 2020 Champions League final.
In May, he refused to play in a match to avoid wearing a rainbow symbol in support of LGBTQ+ rights, BBC Sport understands.
Everton manager Frank Lampard added: "We are delighted to add a player of Idrissa's quality and experience to the squad. We have been eager to strengthen our midfield options and his attributes will undoubtedly benefit the squad.
"Idrissa has played at the highest level of football. Evertonians know all about his tireless work-rate and the value he brings to a team, and we are looking forward to him bringing all of that now he's back at the club."
Meanwhile, Portugal midfielder Andre Gomes, who is yet to feature for Everton this season, is in talks about a move to French side Lille.
Bringing Idrissa Gana Gueye back to Goodison Park is a smart move by Everton. Yes he's into his 30's now but it doesn't seem to matter these days. His style of midfield play is something Everton have needed - he can put his foot in, he can press, break things up and get things moving. That was the hallmark of his time at the club between 2016-19. Fans were sorry to see him go and he'll certainly be welcomed back.
And that's another good thing about this move. He knows the place, he knows the fans. He understands the club, and his settling-in period should be very short as a result.