The 19-year-old joins fellow Reds Raheem Sterling, Jonjo Shelvey and Jordan Henderson in Stuart Pearce’s squad for their two-legged European Championship play-off against Serbia next Saturday and the following Wednesday.
Pearce was full of praise for Sterling, who stepped up to the national squad for their game against Ukraine last month.
"For Raheem, to have an insight into the senior team, is fantastic," he said.
"He's been in our development squads and has done extremely well for Liverpool, and credit to Brendan, who has given him his chance. We are pleased to have him.
Full England U21 squad: Ben Amos (Manchester United), Jack Butland (Birmingham), Declan Rudd (Norwich), Jason Steele (Middlesbrough); Ryan Bennett (Norwich), Steven Caulker (Tottenham), Nathaniel Clyne (Southampton), Craig Dawson (West Brom), Tom Lees (Leeds), Jack Rodwell (Manchester City), Danny Rose (Tottenham), Adam Smith (Tottenham), Andre Wisdom (Liverpool); Jordan Henderson (Liverpool), Tom Ince (Blackpool), Henri Lansbury (Nottingham Forest), Jason Lowe (Blackburn), Josh McEachran (Chelsea), Nick Powell (Manchester United), Jonjo Shelvey (Liverpool), Raheem Sterling (Liverpool), Wilfried Zaha (Crystal Palace); Nathan Delfouneso (Aston Villa), Marvin Sordell (Bolton), Andros Townsend (Tottenham), Connor Wickham (Sunderland).