The Leicester Tigers forwards have played key roles in taking the club to the Guinness Premiership title and Heineken Cup Final this season.
Now they have been named by England manager Martin Johnson in his first team of the summer.
Moody, who has been capped 53 times, will make his first appearance for England since the 2008 Six Nations opener against Wales. He will play alongside Chris Robshaw and Nick Easter of Harlequins in the back row.
Deacon, meanwhile, won the last of his eight England caps against Wales in the 2007 Six Nations and will partner captain Steve Borthwick in the second row.
Deacon and Moody are set to face Tigers teammates Martin Corry, who has been named the Barbarians captain for Saturday's game.
England will then play a two Test series against Argentina at Old Trafford, Manchester on June 6 and Salta, Argentina on June 13.
England
15 Delon Armitage (London Irish)
14 Ben Foden (Northampton Saints)
13 Jamie Noon (Newcastle Falcons)
12 Jordan Turner-Hall (Harlequins)
11 Matt Banahan (Bath Rugby)
10 Andy Goode (CA Brive)
9 Danny Care (Harlequins)
1 Tim Payne (London Wasps)
2 Dylan Hartley (Northampton Saints)
3 David Wilson (Newcastle Falcons)
4 Steve Borthwick (Saracens, captain)
5 Louis Deacon (Leicester Tigers)
6 Chris Robshaw (Harlequins)
7 Lewis Moody (Leicester Tigers)
8 Nick Easter (Harlequins)
Replacements
16 Steve Thompson (CA Brive)
17 Nick Wood (Gloucester Rugby)
18 Chris Jones (Sale Sharks)
19 Steffon Armitage (London Irish)
20 James Haskell (London Wasps)
21 Paul Hodgson (London Irish)
22 Tom May (Newcastle Falcons)
