Due to Slovenia not being on the Irish government's green list amid travel restrictions in place because of the Covid-19 pandemic, the fixture is being played on neutral ground in Hungary at the Szusza Ferenc Stadion, just outside Budapest, and will be one-legged rather than the customary home and away format that will not be used until the play-off round should Dundalk progress that far.
You can watch coverage of the match live on RTÉ 2 and the RTÉ Player from 5.45pm on Wednesday.
You will be able to follow Dundalk v NK Celje via our live blog on RTÉ.ie and the RTÉ News Now app.
THE OPPOSITION'S PEDIGREE
Celje are participating in the Champions League qualifiers for the very first time, having enjoyed the club's maiden Slovenian league title win last season, pipping the country's record champions Maribor by just two points after the season was completed in June and July.
However, while trophies have been hard to come by for Celje over the years, along with Maribor they do share the distinction of never having been relegated from the Slovenian top flight since it was founded in 1991.
While Dundalk will be their first ever Champions League opponents, the club has featured in the Europa League, losing out in the first qualifying round on their last three attempts in that competition over the past decade.
Current manager Dusan Kosic has been in charge since 2017 and former Slovenia, West Brom and Hull midfielder Robert Koren is part of his coaching staff.
Croatian forward Dario Vizinger scored 23 goals last season and won the Slovenian league's young player award, while the club's second top scorer and bearer of the number nine jersey, Mitja Lotric, won the league's overall Player of the Season award after netting 18.
If Dundalk beat Celje, they will then advance to the second qualifying round where the winners of the tie between Norway's Molde and Finland's KuPS await in a match to be played next week. Dundalk have been drawn at home for that tie should they progress.
Watch live coverage of the Dundalk v NK Celje in the Champions League first-round qualifier on RTÉ 2 and the RTÉ Player today from 5:45pm