Saints stars Courtney Lawes and Tom Wood will start for England in the final World Cup warm-up match on Saturday.
And Kieran Brookes also takes his place in the squad for the clash with Ireland at Twickenham, starting the game on the bench.
England kick-off their World Cup campaign against Fiji at Twickenham on September 18.
And the clash with Ireland will be a real test as Stuart Lancaster’s men look to bounce back from a narrow defeat in France.
Lancaster said: “We are excited about this weekend and playing at home and it is another opportunity for these 23 players as we finalise our preparations for the World Cup.
“It’s great to see Brad (Barritt) back along with the guys that missed the Six Nations such as Ben Morgan, Joe Launchbury and Owen Farrell, who now have a Test match under their belts, and it leaves us with lots of options both starting and from the bench.
“The players know that having made the 31 is not enough and we have seen in training how determined they are to be in that squad to play Fiji in the opening game.”
England (v Ireland, Twickenham Stadium, 2.30pm BST, Saturday September 5, 2015)
15 Mike Brown (Harlequins, 38 caps)
14 Anthony Watson (Bath Rugby, 10 caps)
13 Jonathan Joseph (Bath Rugby, 12 caps)
12 Brad Barritt (Saracens, 22 caps)
11 Jonny May (Gloucester Rugby, 15 caps)
10 George Ford (Bath Rugby, 12 caps)
9 Ben Youngs (Leicester Tigers, 48 caps)
1 Joe Marler (Harlequins, 32 caps)
2 Tom Youngs (Leicester Tigers, 23 caps)
3 Dan Cole (Leicester Tigers, 51 caps)
4 Courtney Lawes (Saints, 39 caps)
5 Geoff Parling (Exeter Chiefs, 24 caps)
6 Tom Wood (Saints, 37 caps)
7 Chris Robshaw (capt, Harlequins, 38 caps)
8 Ben Morgan (Gloucester Rugby, 28 caps)
16 Jamie George (Saracens, 1 cap)
17 Mako Vunipola (Saracens, 22 caps)
18 Kieran Brookes (Saints, 11 caps)
19 Joe Launchbury (Wasps, 23 caps)
20 Billy Vunipola (Saracens, 18 caps)
21 Richard Wigglesworth (Saracens, 22 caps)
22 Owen Farrell (Saracens, 30 caps)
23 Sam Burgess (Bath Rugby, 1 cap)