West Ham have announced that David Moyes has succeeded Slaven Bilic as the club's new manager.
Bilic was dismissed by West Ham on Monday, after a run of form that has seen the club drop into the Premier League's relegation zone.
Moyes, who has been out of work since resigning from his role at Sunderland in May after failing to keep them in the top flight, has been charged with turning the club's fortunes around.
"West Ham United can confirm the appointment of David Moyes as the club's manager," a West Ham statement read.
West Ham United can confirm the appointment of David Moyes as the Club's manager. pic.twitter.com/AIOWnHWn27
— West Ham United (@WestHamUtd) November 7, 2017
Moyes said: "I'm really looking forward to meeting the supporters, being in the stadium with them. I'm looking forward to seeing them getting right behind the team and my team also. We need the support, we need everybody with us. It's a big job we have in hand now, but I'm sure with everybody together, we can get the right results between now and the end of the season."
West Ham joint-chairman David Sullivan added: "I would like to welcome David to West Ham United. This is a unique position for David Gold and myself -- it is the first time in almost eight years at West Ham United that we have appointed a new manager during the season.
"We need somebody with experience, knowledge of the Premier League and the players in it, and we believe David is the right man to turn things around and get the best out of the players at the club. He is highly regarded and respected within the game, and will bring fresh ideas, organisation and enthusiasm.
"He proved with Everton that he has great qualities, and we feel that West Ham United is a club that will give David the platform to display those qualities again."
Moyes, 54, spent 11 years in charge of Everton, in which he managed to lead the club to the Champions League and Europa League, while also reaching an FA Cup final.
He was then appointed Sir Alex Ferguson's successor at Manchester United in 2013 but was sacked after just 10 months in charge.
Moyes, who started his managerial career at Preston, also had a stint in La Liga with Real Sociedad but was dismissed nearly one year after taking charge, before embarking on his unsuccessful spell with Sunderland.
Former West Ham defender Stuart Pearce, meanwhile, has been linked with a role on Moyes' coaching staff.
"I've had no contact with West Ham, if that's what you mean, but if I had contact with them, I would certainly go and talk to them," Pearce told talkSPORT.
Moyes' first game as West Ham manager will be the trip to Watford in the Premier League on Nov. 19.