Matthew Healy will start at scrum half for Ireland, with Conor Murray moving to the replacements after starting the game against Italy a fortnight ago.
Ronan O'Mahony, a late try scorer against Italy, has also been promoted to the starting line-up on the right wing in place of Mark Doyle. Shane Gahan takes O'Mahony's place on the bench after returning from injury.
In the forwards, James Sandford and Mark Flanagan swap positions with Sandford starting in the second row and Flanagan named on the bench.
Looking forward to entertaining England, Clarke said: "Friday's game against England will test how far we have progressed as a squad.
"Preparation has gone well and the mood in the camp is very good. We are aware of the challenge ahead and the level of performance required, both from a team and individual viewpoint."
Tickets for Friday's encounter are on sale at The Bounty, Musicworld and Keenan Sports outlets in Athlone, and are also available at Noel Mannion Sports in Ballinasloe and Harten's Newsagents, Moate.
Cash will also be taken at the turnstiles on match night.
IRELAND UNDER-20 TEAM & REPLACEMENTS (v England Under-20s, 2009 RBS U-20 6 Nations Championship, Dubarry Park, Athlone, Friday, February 27, kick-off 6.15pm):
15 - David Kearney (Lansdowne/Leinster)
14 - Ronan O'Mahony (Garryowen/Munster)
13 - Ian McKinley (UCD/Leinster)
12 - Eamonn Sheridan (Lansdowne/Leinster)
11 - Michael Keating (Clontarf/Leinster)
10 - Ian Madigan (Blackrock College/Leinster)
9 - Matthew Healy (Lansdowne/Leinster)
1 - Paddy McAllister (Ballynahinch/Ulster)
2 - Thomas Sexton (Old Belvedere/Leinster)
3 - Jack McGrath (St. Mary's College/Leinster)
4 - Ciaran Ruddock (Neath/Exiles)
5 - James Sandford (Queens University/Ulster)
6 - Rhys Ruddock (Millfield School/Exiles)
7 - Dominic Ryan (Lansdowne/Leinster)
8 - Peter O'Mahony (Cork Constitution/Munster) (capt)
16 - David McGregor (Ballynahinch/Ulster)
17 - Jack O'Connell (Lansdowne/Leinster)
18 - Mark Flanagan (UCD/Leinster)
19 - Michael Noone (Seapoint/Leinster)
20 - Conor Murray (Garryowen/Munster)
21 - Shane Gahan (Lansdowne/Leinster)
22 - Gary Foley (Blackrock College/Leinster)