Celtic face Sarajevo in first Champions League qualifier
Celtic will play Sarajevo of Bosnia-Herzegovina in the first round of Champions League qualifying.
Sarajevo won their domestic league and cup double last season while Celtic were again treble winners.
Northern Irish champions Linfield have drawn Norwegian side Rosenborg and League of Ireland winners Dundalk face Riga of Latvia.
Celtic have reversed their fixtures so will be away in the first leg on 9 or 10 July.
Linfield and Dundalk are all at home first leg with the return a week later.
Welsh champions The New Saints will face the winners of the preliminary round. Gibraltar's Lincoln Red Imps, Andorran side FC Santa Colomo, Tre Penne of San Marino and Kosovo's Feronikeli are the sides involved in the preliminary round.
The draw for the second qualifying round will be held on Wednesday.
Should Celtic fail to get past Sarajevo, they will receive a bye in Europa League second-round qualifying and drop into the third round due to an odd number of teams entering the lesser competition's champions' path.
The Scottish champions began pre-season training on Monday, just over three weeks after ending the campaign in the Scottish Cup final, and some of their players have yet to return after representing their country in Euro qualifying this month.
But left-back Kieran Tierney insists Celtic will be "ready for the challenge" against Sarajevo in three weeks' time.
"They're going to be hard to break down and they'll come at us as well," Tierney, 22, said.
"It's such a short break so we're not coming back unfit. We'll lose a bit but we're still coming back in good shape and good condition."
Celtic failed to make the group stage for the first time in three years last season, losing to AEK Athens in the third qualifying round.
They must make it through four rounds to reach the groups and face a Sarajevo side that defeated Banants of Armenia in their opening qualifier a year ago before losing to Italian outfit Atalanta.
Sarajevo ended a four-year wait for title success last term and their manager, Husref Musemic, had a short playing stint with Hearts in 1989.
Sarajevo have won the Bosnia-Herzegovina league four times and previously lifted the Yugoslav top-flight title twice.