The talented Warwickshire all-rounder is regarded as one of the rising stars of the English game, even though he has still to score his first professional century in any format.
Bethell, however, has still been appointed to lead England in a three-match T20 series against Ireland in Dublin, which will serve as part of the team's preparations for next year's T20 World Cup in India and Sri Lanka.
Should all go according to plan, he will become England's youngest men's captain in an international match, breaking the record of Monty Bowden, who was 23 years and 144 days old when he led England in a Test against South Africa at Cape Town in 1888/89.
Bethell has featured in just four Test matches but has become a white-ball regular with 13 Twenty20 appearances and 12 one-day internationals to his credit since making his T20 bow in September last year.
"Jacob Bethell has impressed with his leadership qualities ever since he has been with the England squads and the series against Ireland will provide him with the opportunity to further develop those skills on the international stage," said England selector Luke Wright.
Bethell's most recent international appearance was in the fifth and deciding Test against India at the Oval earlier this month where, having replaced injured red-ball captain Ben Stokes, he managed scores of just six and five, while not taking a wicket with his left-arm spin.
England lost a thrilling match by just six runs as India ended a gripping five-Test series all square at 2-2.
But former England captain Michael Vaughan said team management had made a "diabolical" decision to call-up Bethell for such a key match on the back of so little first-class cricket this season.
"Jacob Bethell, this summer has faced 67 balls in red-ball cricket, he scored 32 runs," said Vaughan on the Stick to Cricket podcast.
He added: "Surely, if you are trying to develop a young cricketer, you've got to give him time to go there and play cricket. So if it does come that he has to play, at least he has had a bit of game time.
"To throw a kid who's 21 out at the Oval in front of 27,000 when the series is on the line on a pitch that is doing plenty against (Mohammed) Siraj. I thought it was diabolical. I thought it was unfair on the player."