Oxlade-Chamberlain has 16 Premier League appearances to his name - 16 more than Walcott had when he went to Germany - and the Arsenal youngster is reassured to have his team-mate by his side.
"It is massive to have Theo in the squad as well," Oxlade-Chamberlain told Arsenal.com. "To be named in the squad, straight away you think of everyone else there.
"I have been watching the likes of Steven Gerrard, Frank Lampard and John Terry for a number of years on TV and also playing for England. That only seems like yesterday and now I'm going to be going with them, it is a bit daunting but I can't wait.
"Straight away, I thought about how good it would be having Theo there, because I have a mate! I get on well with Theo and when I first came to Arsenal he took me under his wing to help me out.
"I know Theo and I know that he went to a World Cup at 16 and enjoyed it. That obviously gives me inspiration and encouragement and I'm really looking forward to it."