Clyne handed first England call-up
Support for Clyne to be included by manager Roy Hodgson for the Euro 2016 qualifying double header with San Marino and Estonia gathered pace following the full-back's fine start to the Premier League campaign with Southampton.
The 23-year-old has started all six matches for Ronald Koeman's men, who are second in the table behind Chelsea.
On the decision to include Clyne, Hodgson said: "He's impressed us for quite a while, even before the World Cup he was a name we were considering.
"But perhaps we felt other players were in front of him, but since then we've lost Glen Johnson and Kyle Walker to injury. John Stones played there last time but we were looking for candidates for the right-back post."
Midfielder Shelvey is also named in the 21-man party, the Swansea City man has just one cap, which came as a substitute in England's 5-0 thrashing of San Marino in a World Cup qualifier in October 2012.
Arsenal full-back Gibbs has three England caps to his name, but a series of injuries have prevented him from featuring more for his country.
Liverpool's Adam Lallana returns to the fold after missing out in the last squad because of a knee injury, while Fabian Delph keeps his place after impressing on his full international debut in England's opening Group E encounter in Switzerland, which they won 2-0.
Arsenal forward Danny Welbeck scored a brace in that game and he is one of three strikers named this time around alongside captain Wayne Rooney and RIckie Lambert.
The former Manchester United man is brimming with confidence after bagging a hat-trick in Arsenal's 4-1 victory over Galatasaray in the UEFA Champions League on Wednesday.
However, there is no place for Liverpool striker Daniel Sturridge who remains absent with a thigh injury sustained in training before England's friendly victory over Norway last month.
England face San Marino next Thursday, before meeting Estonia in Tallinn three days later.
Squad in full:
Goalkeepers: Fraser Forster (Southampton), Ben Foster (West Bromwich Albion), Joe Hart (Manchester City)
Defenders: Leighton Baines (Everton), Gary Cahill (Chelsea), Nathianiel Clyne (Southampton), Kieran Gibbs (Arsenal), Phil Jagielka (Everton), John Stones (Everton)
Midfielders: Fabian Delph (Aston Villa), Jordan Henderson (Liverpool), Adam Lallana (Liverpool), James Milner (Manchester City), Alex Oxlade-Chamberlain (Arsenal), Jonjo Shelvey (Swansea City), Raheem Sterling (Liverpool), Andros Townsend (Tottenham Hotspur), Jack Wilshere (Arsenal)
Forwards: Rickie Lambert (Liverpool), Wayne Rooney (Manchester United), Danny Welbeck (Arsenal).