The Zambia international, who has scored 32 goals in 84 games for the Super League club, has already been granted a work permit and passed a medical on Tuesday ahead of finalising his move to St Mary's Stadium on a five-year deal.
Saints boss Nigel Adkins has hailed the acquisition of the 21-year-old, telling the club's official website: "Emmanuel is a lightning-quick striker who I am sure will excite the fans.
|OPTIONS UP FRONT|
|9/1||Rickie Lambert is 9/1 with Bet365 to score the first goal in Southampton v Manchester United|
"He will bring something different to the group that we already have here at Southampton, and I look forward to seeing him pull on our shirt for the first time."
Zakuya formed part of Zambia's victorious 2012 Africa Cup of Nations squad, scoring the winner in the semi-final clash with Ghana and netting in the penalty shootout in the final.