The 21-year-old, who joined Celtic from Belgian club Beerschot for £900,000 two years ago, has agreed a four-year-deal at St Mary's.
Kenya international Wanyama was the Scottish Premier League's young player of the year last season and scored a header in the 2-1 Champions League win over Barcelona.
The fee is the highest ever received by a Scottish club for a player, reports the BBC.
"It feels great and I am happy to be here," said Wanyama.
"There were other options, but Southampton is a club with ambitions so I chose to come here.
"Southampton is a good club and it has good players, so I just want to train hard and work hard to be a part of the starting XI. We'll see where that will take me.
"I'm very grateful to be here and I'm looking forward to playing in the Premier League."
He scored nine goals last season, including against Barca.
Following that famous victory, manager Neil Lennon suggested the powerful midfielder was worth £25m.
In October, it was revealed that Wanyama had rejected the offer of a contract extension, with Lennon repeatedly encouraging the player to reconsider.
Wanyama made his international debut in 2007 against Nigeria aged just 15 and moved to Belgium the following year.
The sale of Aiden McGeady from Celtic to Spartak Moscow for £9.5m was the previous record fee paid for a player from Scottish football.
Wanyama is Southampton's second signing of the summer and follows Croatian Dejan Lovren to the club.
No comments:
Post a Comment