Craig Gordon, at 43 years old, has been named to Scotland's 26-man squad for the nation's first World Cup in 28 years.
The veteran goalkeeper joins a squad featuring teammates who were not yet born when Gordon made his international debut in 2004.
If Gordon plays in North America, he will become the second-oldest player in the World Cup's 96-year history, behind Egypt's Essam El Hadary, who was 45 in 2018.
World Cup Group
Scotland has been drawn in Group F alongside Brazil, Morocco, and Haiti.
The team opens its campaign against Haiti on June 14 in Boston, then faces Morocco in Boston before concluding against Brazil in Miami on June 24.
Goalkeeping Selection
Gordon is among three goalkeepers in the squad, though he has dealt with shoulder injuries this season. He made three appearances for Heart of Midlothian in January.
"Craig assures us he's fully fit," Clarke said. "He deserves to go because he played a part of the qualifying campaign."
The other goalkeepers are Angus Gunn of Nottingham Forest and Liam Kelly of Rangers.
Young Talent
Clarke has included two promising young wingers: 20-year-old Ben Gannon-Doak of Bournemouth and 19-year-old Findlay Curtis, who impressed on loan from Rangers at Kilmarnock.
Hearts captain Lawrence Shankland is expected to lead the attack in the group's opening match.
Squad Overview
Napoli's Scott McTominay heads a strong contingent of midfielders playing in Italy's Serie A.
Rangers defender John Souttar is included, with his younger brother Harry set to represent Australia at his second consecutive World Cup.
Clarke noted he had "five very difficult conversations" with players who featured in warm-up games but were not selected.
The notable omission is 19-year-old midfielder Lennon Miller from Udinese, who was widely expected to make the squad.
Full Scotland Squad
Goalkeepers: Angus Gunn (Nottingham Forest), Craig Gordon (Heart of Midlothian), Liam Kelly (Rangers)
Midfielders: Scott McTominay (Napoli), John McGinn (Aston Villa), Billy Gilmour (Napoli), Ryan Christie (Bournemouth), Lewis Ferguson (Bologna), Kenny McLean (Norwich), Ben Gannon-Doak (Bournemouth), Findlay Curtis (Rangers)
Forwards: Lawrence Shankland (Heart of Midlothian), Lyndon Dykes (Charlton), Ché Adams (Torino), George Hirst (Ipswich), Ross Stewart (Southampton)
Scotland has never advanced past the group stage in eight previous World Cup appearances.