Celtic will face AEK Athens in the third qualifying round of the Champions League, if they overcome Rosenborg in the second round.
The Scottish champions play the Norwegians in the first leg in Glasgow on Wednesday, with the return tie in Trondheim seven days later.
AEK Athens won the Greek Super League for the 12th time last season.
They were knocked out of Champions League qualifying in the third-round stage last season by CSKA Moscow.
The Greek side went on to compete in the Europa League group stage, qualifying from a section that included AC Milan, Austria Vienna and Rijeka, before losing in the round of 32 to Dynamo Kyiv.
AEK, who are currently managed by Marinos Ouzounidis, have faced Dundee United and Hearts in European competition in the past 12 years, but have never met Celtic before. Last season's league crown was their first top-flight title in 24 years.
Celtic beat Armenian outfit Alashkert 6-0 on aggregate in the first Champions League qualifying round.