Allen scored twice for Gloucester against Agen on Saturday

The 20-year-old centre, in Harlequins' academy before their relegation saw him join Gloucester in the summer of 2005, has started just 23 senior games.

"It is obviously a fantastic feeling - pretty unbelievable," Allen said.

"At the start of the season I was just concentrating on establishing myself at Gloucester so to be selected for England so quickly is very special."

I just have to concentrate on getting all the small margins in my game right Anthony Allen

Southampton-born Allen first played rugby at Millfield Preparatory School in Somerset before joining the Trojans club in Eastleigh, Hampshire, where his father still coaches the senior sides.

Harlequins spotted his potential but his time there ended when they were forced to cut costs following relegation from the Premiership.

He was picked up by Gloucester, where he is the first Test graduate of a burgeoning young backline also featuring Olly Morgan, Ryan Lamb, Jack Adams and Mark Foster.

"All I can do now is be as professional as I can, keep my head down, listen to the experienced people I have around me and prepare as well as I can for this game," Allen added.

"It's obviously a massive challenge and to play for your country is fantastic but I just have to concentrate on getting all the small margins in my game right, relax and do a good job.

"The England coaches said my game stepped up against Leinster and again at the weekend as well. They think I am playing well and have picked me on form."