Both Scottish League Cup semi-finals will be staged at Hampden Park next month.
Championship side Morton take on Aberdeen in a 12:15 BST kick-off on Saturday, 22 October.
Scottish Premiership leaders Celtic meet Glasgow rivals Rangers on the following day at 14:15.
BBC Radio Scotland will provide live commentary of both matches, with the online broadcast supplemented by text coverage on the BBC Sport website.
Celtic were 5-1 winners against Rangers when they met on league duty at Celtic Park on 10 September.
But Rangers won a penalty shoot-out when the sides met at Hampden in the last four of the Scottish Cup last season, with Celtic prevailing at the same venue at the same stage of the League Cup in 2015.
This is the fifth time Morton have reached this stage of the tournament, the most recent coming in 1979 when they lost out to Aberdeen.
The Dons, who have won the League Cup on six occasions, have beaten the Greenock outfit another four times in the competition since that Hampden victory.