Former England boss Sam Allardyce returned to management for the first time in two-and-a-half years after being appointed as West Brom manager on Wednesday.
Allardyce, 66, takes over the Premier League strugglers after Slaven Bilic was sacked despite earning a 1-1 draw at Manchester City on Tuesday.
The Baggies are 19th in the table, but sit just two points off safety.
Allardyce has joined on an 18-month contract and will take charge for the first time in a Midlands derby against Aston Villa on Sunday.
"In Sam we have a man who has a proven Premier League pedigree with a track record of improving every club he has managed," said Luke Dowling, West Brom's sporting and technical director.
"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."
Bilic led West Brom back to the top-flight in his only full season in charge, but paid for winning just one of the club's first 13 Premier League games of the campaign.
The Croatian's relationship with the club's board had also soured in recent months after he was given little funding to bring in players in the close season.
"West Bromwich Albion have today parted company with Head Coach Slaven Bilic," the club said in an earlier statement.
"Albion would like to thank Slaven and his coaching staff for their efforts in achieving promotion last season and wishes them all well in the future."
Bilic is the first Premier League manager to be sacked in over a year as a three-month stoppage due to the coronavirus pandemic and empty stadiums since the return of English football has led to greater patience with coaches.
Allardyce has not been involved in a coaching role since leaving Everton in May 2018.
But he has a wealth of experience when it comes to keeping sides in the Premier League and now takes charge of a record eighth club in the English top-flight after previous spells at Bolton, West Ham, Newcastle Blackburn, Sunderland and Crystal Palace.