Ward-Prowse and Oxlade-Chamberlain became best mates after graduating from Saints' prolific youth academy at the same time.
He said: "I was good friends with Alex and seeing his success has inspired me to do the same.
"He has done fantastically well and I am really pleased for him.
"When he was here, we used to catch the train to training together every day because we both lived in Portsmouth. We had to hide our club tracksuits in case we got any stick from Pompey fans.
"He is my mate, but we will put that aside. I'll go out and do what is right for the club and for my team-mates."