The Official Online RBS 6 Nations Store is open. The store has everything you need to get behind your team during the RBS 6 Nations, plus the store is now fully stocked with a much wider range of rugby merchandise.
The Wasps scrum-half's surprise call-up came after Danny Care was ruled out of the tournament with a toe injury he sustained against Wales last Saturday.
Simpson is likely to make his international debut in England's final warm-up match against Ireland on Saturday after being named on the bench.
The 23-year-old has previously featured in England squads, but failed to win his first cap after dislocating his shoulder before the 2010 RBS 6 Nations and tweaking his hamstring before the summer tour to Australia of that year.
Simpson is eager to repay Martin Johnson's faith in picking him, whilst more experienced players such as fly-half Riki Flutey have been omitted from the 30-man squad.
“I wouldn't consider myself a wild card," said Simpson. “I like to think that I can play a very expansive game and make breaks that maybe other number nines can't.
“I'm hoping to just play my game and play England's game. I'm not going to go away from what England do as a team, I'm not going to do anything off the cuff.
“A lack of international experience is something I will have to adapt to, but I believe I have the ability to take it in my stride. I am desperate to represent England in such a major tournament.
“I try not to get too worked up or nervous before matches, I try to enjoy them. I'm going to try to keep to my pre-match routines and not change much.
“Obviously there's going to be a lot of added pressure for myself, but it's something I'm confident I can deal with.”
Meanwhile, Johnson has been forced into a late reshuffle to his starting XV against Ireland after Nick Easter withdrew from the squad with a tight calf.
James Haskell fills the void at No.8 with Hendre Fourie coming in at openside even though the flanker was not included in England's final 30-man World Cup squad.