The 22-year-old signed for the Saints for £12.5 million from the SPL champions this summer, and admits he still holds his former club's supporters in his heart following his exit
The 22-year-old signed for the Saints for £12.5 million this summer after winning the SPL with Celtic last season.
And having made 32 appearances in 2012-13 for the SPL champions, the midfielder admits he would be open to a move back to the Scottish club in the future.
"It was hard leaving them [Celtic], they were good to me but I wish the fans all the best," he told reporters. "Hopefully one day we will be back."
Wanyama will also become the first player from Kenya to play in the Premier League when he is handed his debut, and is eagerly anticipating getting started in England.
He added: "I'm excited, it's a new challenge to play in the Premier League.
"It means a lot to be the first Kenyan in the Premier League but I have to work hard to get in the team and then we will see from there."