The young Magpies' Group G encounter against their Hornets counterparts was due to kick-off at 6pm (GMT) on Friday, 10th December but will now begin at 4pm, taking place at Whitley Park.
Newcastle's youngsters currently sit in third place on four points, with three group games remaining, but can move above the Hertfordshire-based outfit with a much-needed victory.
The top two sides in the group will qualify for the knockout stages of the competition. United's second-string completed a memorable run to the 2019 final before losing out to Everton in a 1-0 defeat at Goodison park.