Local draw for Joe's side.
We'll have more news on this soon - the two teams play their replay on Tuesday night and we'll have ticket details as soon as they are released following the result of that tie.
Chelmsford looked destined for the First Round after leading their game at the weekend, before Thurrock equalised deep into injury time.
That game will come after the trip to Shrewsbury and before the home game against Notts County.
The U's, who have won four of their five league games under Joe's management will face the winners of the replay on the weekend of November 3rd.
The draw, which was made on Sunday afternoon, paired Joe Dunne's side with either local neighbours Chelmsford City or East Thurrock in a tantalising First Round tie.
The U's will face an Essex derby in their opening FA Cup game of the season.