The Glasgow Hawks prop has joined the Warriors on a two-year deal. He's joined in the Scotland starting line-up by fellow Hawks George Horne and Scott Cummings with Andrew Davidson on the bench.
Scotland went down to a heavy 68-10 defeat at the hands of New Zealand in the opening match of the competition.
Scotland under-20 Head Coach, Sean Lineen, has made eight changes to his starting side for game - kick-off 3.30pm GMT – live on BT Sport 2.
After dropping out through illness for the opening tie against New Zealand, wing Robbie Nairn comes in to make his first start for Scotland under-20, with Ruairi Howarth and Alec Coombes retaining their spots at full-back and left wing respectively.
Patrick Kelly comes in at inside-centre, with Tom Galbraith sliding out one spot to occupy the 13 shirt. Archie Russell is unavailable for selection as he serves a two-match ban for a dangerous tackle.
Blair Kinghorn makes his first start for Scotland under-20, slotting in at stand-off, and will be partnered by inbound scrum-half George Horne.
The duo of Murray McCallum and Zander Fagerson – a pairing who started all five games in the Six Nations – come in to start at front-row to support encampment hooker Sam James.
Try-scorer against New Zealand, Lewis Carmichael, will once again start in the boiler room alongside Scott Cummings.
Openside flanker Jamie Ritchie resumes his captaincy duties, with Neil Irvine-Hess and Magnus Bradbury promoted from the bench to join him in the back-row. Last week’s starters, Ally Miller and Lewis Wynne, are unavailable for selection due to injury.
Sean Lineen said: “We always knew it was going to be tough with five games in 18 days. It’s a quick turnaround and a busy tournament, and with such comes a lot of change in the squad.
“Our first game against New Zealand was very tough, physically and mentally, yet Ireland are in the same boat after their close encounter with a big Argentina side.
“Some boys included in this match-day squad have been out here for nearly two weeks and haven’t played yet, so they’re champing at the bit to get out there.”
The last time the two teams met was in the final round of the 2015 Six Nations, with Scotland taking the plaudits, recording a 17-10 victory to achieve a record finish.
However Lineen has made it clear to his squad that the World Championships are a very different competition.
“Teams will have continued to work hard to improve over the period in between the two tournaments, so we are aware that we won’t face the same Ireland team as we did at Netherdale back in March,” he continued.
“There is no doubt that we’re in for another very tough and tight encounter, but, as always, we’ll go out there and embrace the challenge.”
Scotland U20
15 Ruairi Howarth (Edinburgh Rugby/Gala)
14 Robbie Nairn (Harlequins)*
13 Tom Galbraith (Melrose)
12 Patrick Kelly (Le Parc)
11 Alec Coombes (London Scottish)
10 Blair Kinghorn (Edinburgh Rugby)*
9 George Horne (Glasgow Hawks)
1 Murray McCallum (Aberdeen Grammar Rugby)
2 Sam James (Bedford Blues)
3 Zander Fagerson (Glasgow Warriors)
4 Scott Cummings (Glasgow Warriors/Glasgow Hawks)
5 Lewis Carmichael (Melrose)*
6 Neil Irvine-Hess (Melrose)
7 Jamie Ritchie CAPTAIN (Edinburgh Rugby)
8 Magnus Bradbury (Edinburgh Rugby)
Substitutes
16 Ross Graham (Hawick)
17 Dan Elkington (Watsonians)
18 Jack Owlett (Exeter University)
19 Andrew Davidson (Glasgow Warriors/Glasgow Hawks)
20 Ruaridh Knott (Melrose)
21 Ben Vellacott (Gloucester/Hartpury College)
22 Rory Hutchinson (Northampton Saints)
23 Richard Galloway (University of Birmingham)
*sportscotland institute of sport supported player 2014/15