European governing body for the sport has opted to move back the date when the teams that are still in the two club competitions will find out their knockout-round opponents.
The event was initially due to take place on Dec. 14, but has now been postponed by six days for unknown reasons.
"The draws for the knock-out rounds of the 2012/13 UEFA club competitions – originally scheduled for 14 December - will now take place on Thursday 20 December at the House of European Football in Nyon, Switzerland," the governing body released in an official statement.
"The pairings for the Round of 16 of the UEFA Champions League, as well as the Round of 32 and Round of 16 of the UEFA Europa League, will be drawn at ceremonies to be staged at UEFA, starting at 11:30 CET and 14:00 CET, respectively."
The final of the Champions League takes place at Wembley on May 25, 2013, with the Europa League showpiece being held at the Amsterdam ArenA 10 days earlier.