Michail Antonio has become West Ham's 12th signing of the transfer window, arriving from Championship side Nottingham Forest on a four-year deal.
West Ham have spent an undisclosed fee on the winger, who could see his contract extended by a further two years.
The Hammers have been deadline day's busiest club so far, with Antonio joining Alex Song, Nikica Jelavic and Victor Moses in making last-gasp moves to Upton Park.
"I'm buzzing and finally happy to be back in London at a massive club," Antonio told West Ham's official website.
"I've always been around London and I came to a couple of games here when I was younger, so I'm happy to be finally here and at a club I watched when I was younger.
"I've worked my way from non-league and finally got to the Premier League to show what I can do, and if the fans don't know me from the Championship, what I bring to the table is pace, power and goals, so hopefully I can do that this season.
Antonio joined Forest from Sheffield Wednesday in August last year and scored 19 goals in 54 appearances for the City Ground club.
