Walcott kicked off his career at St Mary's before moving to Arsenal.
"Theo has done a brilliant job and is a great player but although I play on the wing, I believe I am a different type of player," said Oxlade-Chamberlain, who has added his mother Wendy's maiden name to keep the name for future generations.
"This is the first season I have played on the wing as I have always played down the middle and long term, that is where I would like to play.
"Theo has probably got more pace off the mark than me while I think my main strength is bringing other players into the game. But to see how well Theo and Gareth have done in their careers after starting out at Southampton shows what a good job they do here.
"They have a good recruitment policy and excellent coaching and facilities. And the coaches are always encouraging us to try new and different things.
"I'm only 17, and I am always looking to improve on every aspect of my game and gain experience."