The Surrey batsman has been rewarded for his starring role at the top of England's limited overs side, including his performances in helping England win the World Cup.
National selector Ed Smith confirmed Roy would make his bow against Ireland as he bids to secure a place at the top of the order for the Ashes series starting on August 1, while Warwickshire's Olly Stone and Somerset's Lewis Gregory may also make their debuts at Lord's.
But introducing new players into the Test side has not been entirely successful for England in recent years. Of the last 20 debutants, dating back to 2016, only five are still in the squad for this Ireland match and pre-Ashes training camp.
Since Craig Overton's maiden appearance in December 2017, England's 10 debutants have a total of 36 caps between them from the 19 Tests the team have played – with Sam Curran's nine caps the most any of those players have managed.
Here, PA takes a look at how those most recent players to be handed a Test cap have fared.
Craig Overton, Somerset – 3 Tests
The paceman made his debut during England's comprehensive series defeat at the hands of Australia in the last Ashes in 2017-18. He started well, taking six wickets in his first two Tests and was selected again against New Zealand in March 2018. But that was his last outing and indifferent county form has meant England have looked elsewhere.
Tom Curran, Surrey – 2 Tests
The elder of the Curran brothers has made his name in one-day cricket in recent years and was an unused member of the World Cup-winning squad. But he too made his Test debut in that 2017-18 Ashes series. Just one wicket in each of his two Tests was underwhelming and he has not returned to the Test arena.
Mason Crane, Hampshire – 1 Test
Crane was handed his bow in the final Test of that series, with England already 3-0 down. It was a baptism of fire for the raw 20-year-old leg-spinner and he took one for 193 in the match. That bruising experience was his one and only Test outing to date and he is well down the spin-bowling pecking order.
Jack Leach, Somerset – 4 Tests
Leach's four Test caps spread across 2018, making his debut in New Zealand before returning for the tour of Sri Lanka. He has impressed on the Test stage, with 16 wickets, and consistently strong form for Somerset means he is in contention to be the lead spinner for England in the Ashes.
Dom Bess, Somerset – 2 Tests
Was handed a surprise Test call in May 2018 aged 20 after Leach broke a thumb after starring alongside his team-mate for Somerset. He claimed three for 49 in his second – and currently last – Test while also impressing with the bat. This season he has struggled to dislodge Leach at county level, leading to a loan move to Yorkshire.
Sam Curran, Surrey – 9 Tests
The Surrey all-rounder was the star of last summer. He made his debut against Pakistan aged 19, before shining against India. Curran has taken 15 wickets in nine Tests and boasts a batting average over 30. But he failed to repeat his form overseas during the winter, taking just two wickets. He is likely to feature against Ireland to try and secure an Ashes spot.
Ollie Pope, Surrey – 2 Tests
Pope was another Surrey youngster to be rewarded for excellent county form when the 20-year-old was brought in for the second Test against India. But he managed a high score of just 28 in his two Tests and was promptly discarded. He has missed the bulk of this season after dislocating his shoulder in April.
Rory Burns, Surrey – 6 Tests
The left-handed opener was the star of the County Championship last season, topping the scoring charts as Surrey won Division One. That earned him the spot as England opener after Alastair Cook's retirement and he has done enough to keep his spot, while not fully convincing in Sri Lanka and the West Indies. Burns has two half-centuries from his 12 innings and will want to find top form to secure his place.
Ben Foakes, Surrey – 5 Tests
When Roy makes his Test bow, that will mean five of England's last six debutants have come from Surrey. Wicketkeeper-batsman Foakes was the last of those and he is battling for a middle-order spot against Ireland. A century on debut against Sri Lanka underlined his ability, while some battling innings under pressure have kept him firmly in the selectors' thoughts.
Joe Denly, Kent – 2 Tests
The call-up of Kent's Denly at the age of 32 was a departure from England's youthful recent selections. He came in to open on debut but was then moved to bat at number three – where he is most likely to bat against Ireland – in his second Test and made a half-century. Denly was dropped at the last minute from the World Cup squad and will be itching to make the Ashes.