Perez becomes the eighth player to join West Ham ahead of the 2018-19 season, and he will compete with fellow new signing Andriy Yarmolenko for a place in Manuel Pellegrini's starting line-up.
The midfielder previously had a stint at Aston Villa and made 48 Premier League appearances for the club before they were relegated to the Championship in 2016.
'I chose to come here because, first, it is the Premier League, second, it's a lovely club and the fans are always helping the club and, third, for me it's an wonderful opportunity and an awesome project the club are leading, being ambitious and keen to achieve good things.
Tribune calls off $3.9 billion deal with Sinclair
Kern said he would continue to run the company until Tribune reached a "permanent state". In addition, Tribune said, Sinclair outright refused to sell station in some markets.
Lucas Perez has thanked former club Arsenal for their "love and affection" following his move to West Ham United. West Ham have great fans and play in an fantastic stadium, so to sign here brings me great joy.
Sanchez's future appears to be away from Fiorentina after spending last season on loan at La Liga side Espanyol.
Perseids 2018: Where and how to watch the dazzling meteor shower
The 2018 Orionid meteor shower will be visible from October 2 to November 7 and is expected to peak on the night of Oct. 21-22. The August shower gets its name from the constellation Perseus because the meteors appear to originate there.
But Press Association Sport understands a transfer across London to join the Hammers is edging closer as Thursday's transfer deadline approaches, with Perez wanting another chance to make his mark in England.
"Lucas is a very experienced player that Manuel and I both know well from Spain", Husillos said on the club website.
West Ham United have landed the signature of Colombia global Carlos Sanchez.
Israel reveals 'impenetrable' sea barrier on Gaza coast
The Israel Defense Forces confirmed in a statement that an aircraft fired at the group in the northern Gaza Strip. Hamas has acknowledged that dozens of those killed were its members.