Former West Ham captain Kevin Nolan has returned to the club as a first-team coach.
Ex-England coach Paul Nevin has also joined the coaching staff of boss David Moyes, with both agreeing initial deals until the end of the season.
Nolan, who spent four years as a Hammers player between 2011 and 2015, started work at his old club on Thursday morning alongside Nevin and fellow coaches Alan Irvine and Xavi Valero.
West Ham manager Moyes told whufc.com: "We welcome Kevin and Paul to the club and look forward to working with them.
"Both have a wealth of experience in the game and I'm sure they will make a very positive contribution between now and the end of the season.
"Kevin obviously knows the club very well having played here previously, while Paul's coaching pedigree is excellent.
"It has taken some time to finalise the coaching staff, but I wanted to make sure I brought in the right people to help us, and both Kevin and Paul are fantastic additions.
"They will get working right away and we are all completely focused on the job we need to do in the coming weeks and months."
Nolan made 157 appearances for West Ham and scored 31 goals, leading the club back to the Premier League in his first season at Upton Park.
Since departing the Hammers, the 37-year-old has had managerial roles at Leyton Orient and Notts County.
Nevin has coaching experience at Fulham, Norwich and Brighton while in 2018 was invited by England manager Gareth Southgate to join his coaching staff.
He was part of the Three Lions group which secured a third-place finish in the 2019 UEFA Nations League finals.