The mouth-watering clash between the two teams that share a total of 11 titles will be held at the Sohar Sports Complex.
The eight last-16 matches will be held on December 9-10 with the schedules yet to be finalised. Saham has been a force to reckon with in the HM's Cup in recent times as it had won the last edition and also won in 2010.
Fanja won its record ninth crown in 2014, but it came after a gap of 23 years. Another strong title contender and eight-time champion Dhofar will travel to Nizwa to take on second-division side Hamra, while former winner Al Suwaiq will host Al Mudhaibi in Sohar.
Al Nahda will host two-time winner Oman in Buraimi, while Nizwa hosts Al Khabourah in another last-16 match.
Al Shabab will host Al Salam at the Seeb Sports Stadium and Jalan will host Sohar at the Sur Sports Complex. Bausher will take on Muscat at the Sultan Qaboos Sports Complex.
The draw ceremony was held under the auspices of Mohsin al Masroori, first vice-chairman of the Oman Football Association (OFA), in the presence of Saad al Jenaibi, QNB Oman's general manager, Sheikh Shabib al Hosni, the CEO of the OPL, and club representatives.
Last-16 matches: Al Nahda vs Oman, Nizwa vs Al Khabourah, Al Shabab vs Al Salam, Al Hamra vs Dhofar, Saham vs Fanja, Jalan vs Sohar, Bausher vs Muscat, Al Suwaiq vs Al Mudhaibi.