Walker will make his debut at the Cathay Pacific HSBC Hong Kong Sevens (March 23-25).

England are fourth in the series behind New Zealand, Fiji and South Africa after five of the nine events which included their tournament victory in Dubai in December.

The three-day, 12-team tournament sees England play Argentina (12:30 GMT) on March 23, and Kenya (03:20) and Samoa (11:30) on March 24 before the following day's knock-out stages.

Head coach Ben Ryan said: "The margins between the sides at this level are very small but we've come up short a couple of times. We haven't spent the last month changing anything but we've been working harder than ever at this phase of the season and making sure everyone is doing everything they can at the highest standard possible.

"The whole squad are in superb shape physically and we're really focused on putting things right, starting in Hong Kong which is a home from home for us. We all want to improve on last year's final appearance and we know we'll get fantastic support from a huge ex-pat crowd."

England Sevens squad:

Greg Barden (captain), John Brake, Chris Cracknell, Isoa Damudamu (British Army), Christian Lewis-Pratt, Tom Mitchell (Oxford University), Dan Norton, Tom Powell, James Rodwell, Mathew Turner, Rob Vickerman, Charlie Walker (Harlequins). Sam Edgerley (Rosslyn Park) will replace Damudamu for the Japan Sevens in Tokyo.

HSBC Sevens World Series (top eight, after five events):

1 New Zealand 92pts,
2 Fiji 87,
3 South Africa 76,
4 England 74,
5 Samoa 69,
6 Australia,
7 France 52,
8 Wales 51.