* Haller joins for reported 45 mln pounds
* Striker signs five-year contract
* West Ham have option to extend by one year (Adds quotes, background)
LONDON, July 17 (Reuters) - West Ham United have signed French striker Sebastien Haller from Bundesliga team Eintracht Frankfurt for an undisclosed club record fee, the Premier League club said on Wednesday.
The 25-year-old joins on a five-year deal with an option of a further year, becoming the Londoners’ fourth signing of the close season.
British media reports put the figure at 45 million pounds ($56 million).
Haller said West Ham’s willingness to break their transfer record had filled him with confidence and promised to repay the club “every day in every game”.
"It means a lot (to be the record signing)," he added in a statement on West Ham's website here "It proves that the club (has) really wanted me for a long time."
West Ham’s previous record signing was attacking midfielder Felipe Anderson from Lazio last July for a reported initial 35 million pounds, rising to a potential 42 million.
Manager Manuel Pellegrini has been searching for a centre forward since allowing Austria international Marko Arnautovic to join Chinese champions Shanghai SIPG earlier this month.
West Ham also released the often injured Andy Carroll at the end of his contract and tried to sign Maxi Gomez from Celta Vigo before the Uruguayan forward joined Valencia instead.
Haller is a former France under-21 international who came through the ranks at French club Auxerre before moving to Dutch side Utrecht in 2015.
He joined Frankfurt two years later and scored 20 goals in 41 appearances in all competitions last season.
“It’s no secret that we have been in the process of identifying a top class striker... and much work has gone on behind the scenes to ensure that we were in a position to act once the right opportunity became available,” West Ham’s director of football Mario Husillos said.
“Sebastien is a player we have been watching closely for some time - he has always been a key target and someone who myself, Manuel Pellegrini and (joint-chairman) David Sullivan were very keen to bring to the football club.”
Haller will join up with the rest of the team when they return from their pre-season tour of China, where they are playing in the Premier League Asia Trophy.
$1 = 0.8057 pounds Reporting by Alan Baldwin and Simon Jennings, editing by Ed Osmond and Christian Radnedge