West Brom have appointed Sam Allardyce as their new head coach.
The former England boss has signed an 18-month contract, which includes a break clause at the end of the season if the Albion are relegated.
Allardyce, in his first managerial role since being sacked by Everton in 2018, replaces Slaven Bilic after he was dismissed on Wednesday following West Brom's 1-1 draw at Manchester City on Tuesday night.
West Brom sporting and technical director Luke Dowling said: "In Sam we have a man who has a proven Premier League pedigree with a track record of improving every club he has managed.
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"We believe and, more importantly, Sam believes we have a group of players that have the quality needed to give the club its best chance of Premier League survival."
The Baggies have struggled on their return to the Premier League this season, winning just once - against bottom club Sheffield United. They remain second bottom of the table, but are only two points behind 17th-place Burnley.
Allardyce sees the job as an ideal opportunity for him to return to football after more than two and a half years away, and the former Bolton, Blackburn and West Ham boss will receive a seven-figure bonus if West Brom avoid relegation.
He is currently still at his home in the North West, but he will need to undergo a coronavirus test before he can travel to the Midlands and enter West Brom's secure eco-bubble.
'Etihad irony - but Allardyce a big character'
Sky Sports News' Rob Dorsett:
The irony is that Slaven Bilic will probably feel very strongly that West Brom had their best performance and result of the season against Man City.
It will be sad news for a lot of West Brom fans. Bilic was a popular figure. He wore his heart on his sleeve and he will feel that he didn't get the resources in the summer transfer window to strengthen.
Slaven Bilic was frustrated that he couldn't get his top targets but West Brom's bosses thought they went above and beyond to support him in the market and gave him more money than they had originally planned. There was definitely a difference in opinion there.
But results speak for themselves - just one win this season, second-bottom of the Premier League. The bosses at West Brom clearly felt the only way for them to mount a realistic survival challenge was to change the manager.
How will the appointment of Allardyce go down with supporters? He's hugely experienced and has a brilliant record of keeping teams in the Premier League. It's that simple.
They may have some concerns about the style of play. Allardyce has never made any apologies for that - he focuses on winning football. But there are a lot of creative players in this side and one of the problems West Brom have had is not scoring enough goals. That's an issue that needs addressing.
The congested fixture list means it may not be easy to change the tactics too quickly but the team that went to the Etihad showed great strength of character and that will give the squad - and the new manager - an awful lot of confidence. Allardyce has been out of the game for a while but he's a big character and a hugely talented manager and he'll make West Brom much more difficult to beat.
I don't think Allardyce would take this job unless he believes he can keep West Brom in the Premier League. He sees himself as a Premier League manager. If he thought they were certain to drop into the Championship, I don't think he'd be interested. But he will want to know they have the resources in January.