The 17-year-old winger is set to play the biggest match of his burgeoning career on Sunday when the two teams contest the Carling Cup Final at the Millennium Stadium, Cardiff. And Jose Mourinho's side are intent on biting the hands that used to feed them - footballs that is.
Walcott might have been playing for Chelsea on Sunday. Even before he had reached his teenage years they had spotted his talent and invited him to Stamford Bridge to help out.
"Yeah I was 10 going on 11 when I was a ballboy there," he said. "There was always a chance I could have gone to Chelsea.
"I was playing in Jersey and their scouts were there. They invited me to come down for the Liverpool match because I was a Liverpool fan.
"I remember Liverpool lost 2-0 and I didn't get a touch of the ball but at least I got to watch it. And I met some of the players - Robbie Fowler and Michael Owen - afterwards in the dressing room. It's funny because when I went to the World Cup I showed Michael a picture of it.
"But I was more interested in the Academy then to be honest. At a young age you just want to play football. It was always going to be Southampton."
Walcott's selection in Germany only added to the hype that has surrounded him ever since he signed for Arsenal last January. The player himself accepts the past year has not been a smooth ride but opportunity has knocked loudest in the Carling Cup.
"I just think we've got better every round," he said. "To go away to Tottenham and get that result was brilliant, I thought. It's not an easy place to go to I'll tell you that now. I thought Portsmouth was bad but we showed character at 2-0 down with all the fans against us. I thought our supporters were brilliant, Julio's two goals were brilliant and the whole squad were brilliant.
"But overall it has been hard because you just want to play. I'm only 17 and playing in the first team at Arsenal, probably the best club in the world I'd say. So I've got a long way to go yet.
"Still to be here in my first year and be in a cup final so early, I didn't expect that. It is a dream come true."
Copyright 2015 The Arsenal Football Club plc. Permission to use quotations from this article is granted subject to appropriate credit being given to www.arsenal.com as the source 23 Feb 2007