The whistler will officiate a major final for the first time in his career after rising up the ranks in the past five years.
The last Celtic match he refereed came earlier in this campaign as Brendan Rodgers’ side drew 0-0 with St Mirren.
Dallas produced a red card for midfielder Olivier Ntcham on that evening, a decision which irked the Celtic boss.
His last match involving Aberdeen saw Derek McInnes’ side earn a 1-1 draw at Easter Road. Like Rodgers, the Dons manager wasn’t happy with the official, whom he believed miss a blatant penalty in the first half.
His assistants at Hampden Park will be Graeme Stewart and Frank Connor, while Nick Walsh is the fourth official.