The 21-year old defender has signed a four-year deal with the Saints, who are back in the top flight, and he is excited about the challenge with his new club after departing Championship outfit Crystal Palace.
"I want to test myself against big players, and hopefully I'll be able to do that this season.
"As soon as I heard that Southampton were in for me, I was happy and I knew that this was the place where I could try to improve my football, further my career and get a chance to play in the Barclays Premier League.
"I've got to hit the ground running in training to show the gaffer that I'm determined to try and get my spot. Hopefully I can please everyone."