The 17-year-old Wolves defender will play against Malta before he has even made his senior debut for the Molineux club. Green said: "I'm overjoyed. It's hard to take in considering I haven't played in Wolves' first team yet.
"I realise it's Giggs' record that I'm overhauling and that makes it an even greater honour for me. It's been a tremendous end of the season for me. I will have played for Wales at youth, Under-21 and full international level all in the last couple of months.
Green will be 17 years and 218 days old, whereas Giggs was 17 years and 321 days old when he won his first full cap against Germany in 1991.
The Wales manager, Bobby Gould, will also give Norwich City's Craig Bellamy and Southampton's Andy Williams their first full appearances after previously only coming on as substitutes in the recent games with Brazil and Jamaica.
Gould's squad had a troubled journey to Malta. They spent two hours sitting on the tarmac at Heathrow airport on Monday night and then another five waiting inside the terminal for emergency repairs to be completed on their plane before they could finally make the trip to Valletta.
Jim Whitley will make his Northern Ireland debut against Spain in tonight's friendly in Santander, while Gerry Taggart returns to the defence.
The Manchester City midfielder, who was approached by Wales, will win his first cap at any level in a five-man midfield against the World Cup- bound Spanish hosts.
The Bolton central defender Taggart, meanwhile, is back after missing the Northern Irish manager Lawrie McMenemy's first two games in charge through injury.
The Luton defender Darren Patterson, who scored the only goal against Switzerland in Northern Ireland's last match, makes way for Taggart.
As expected, the Sheffield Wednesday midfielder Jim Magilton starts in place of the injured Steve Lomas, while the Birmingham City winger Jon McCarthy replaces the injured Keith Gillespie on the right flank. It leaves the West Bromwich striker James Quinn as the odd man out in McMenemy's 4-5-1 formation.
Iain Dowie, who will captain the Irish in the absence of Lomas, said: "We have not come here to be anybody's patsies. We quite like having our backs to the wall - because that's when we are at our best."
WALES (Friendly v Malta, Valletta, today): P Jones (Southampton); Green (Wolves), Pembridge (Sheffield Wednesday), Bellamy (Norwich), Ready (Queen's Park Rangers), Coleman (Fulham), Williams (Southampton), Saunders (Sheffield Utd), Hartson (West Ham), Trollope (Fulham), Speed (Newcastle).
NORTHERN IRELAND (Friendly v Spain, Santander, today): Fettis (Blackburn), Jenkins (Dundee Utd), A Hughes (Newcastle), Taggart (Bolton), Morrow (Queen's Park Rangers), Lennon (Leicester), Jim Whitley (Manchester City), Magilton (Sheffield Wednesday), McCarthy (Birmingham), M Hughes (Wimbledon), Dowie (Queen's Park Rangers).