Walcott was thrust into the media spotlight when he joined Arsenal in a big-money move from Southampton as a 16-year-old, and then being included in Sven-Goran Eriksson's 2006 World Cup squad.
Although Walcott did not get a game in Germany, four years on he will be keen to make a lasting impact on the biggest stage of all in South Africa.
On the mark: Arsenal and England footballer Theo Walcott
Walcott has had to deal with carrying the expectation of a nation on his shoulders, increased by a stunning hat-trick in the qualifying victory away to Croatia in September 2008, currently his only international goals.
A succession of niggling injuries and a club v country row following his inclusion in last summer's European Under-21 Championship squad, have all taken their toll.
Familiar: Walcott has been blighted by injuries this season and his form has suffered
The critics were quick to jump on the anti-Walcott bandwagon following a subdued display in the recent friendly against Egypt, with Chris Waddle going as far as to claim Walcott did not have a 'football brain'.
However, Walcott provided the perfect answer with a match-winning display three days later as he slotted in a well-taken goal during the 3-1 Barclays Premier League win over Burnley.
With Tottenham winger Aaron Lennon struggling to overcome a groin problem and veteran David Beckham ruled out of a fourth World Cup after rupturing his Achilles, Walcott's place on the plane to South Africa would perhaps seem somewhat more secure.
However, the youngster will take nothing for granted as the Gunners chase domestic and European honours, happy to just let his football do the talking.
'I have had so many injuries this season, people don't realise how hard it is to come back from setback after setback after setback,' Walcott said.
'You can't be at your best straight away and if you think you can, then you put more pressure on yourself. That's what I had been doing this season.
'The best thing is I do know what's going on on the outside, but I don't listen to it, I only listen to people around me. It's doesn't bother me whatsoever. Maybe if I keep performing like I have it will shut people up.'
Walcott added: 'My development has gone very well. I am only 20 still and I have been in the limelight all the time.
Rapid rise: Walcott joined Arsenal as a 16-year-old (above) and within four years had scored a hat-trick for his country (below)
'As a young player you normally do your development in the background and build yourself up, but the World Cup 2006 call-up shot the pressure on me straight away.
'The thing is I am always the country's biggest hope or the country's biggest disappointment, and I think I dealt with that quite well. Now I have had experience, I played in the Under-21s and played in the Premier League.
'There is definitely more to come from me, but those experiences will now move me on to great things.'
Gunners boss Arsene Wenger has every confidence Walcott can become one of England's finest players.
'I believe for a while maybe people expected too much of Theo and now they are too hard with him,' the French coach said.
'I believe Theo will be a great football player, he is very young, he will be 21 this year, he will have a great future.
'I believe in him because he has a fantastic attitude, he's an intelligent boy and he is highly motivated. These players always improve.'
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