The Hornets have been drawn away to the Premier League champions in the third round of the prestigious competition, which will take place during the first weekend of January.
As well as giving his promotion-chasing side the chance to test themselves against one of Europe's elite teams, Zola will come up against former Italy international team-mate Roberto Mancini in the opposite dugout.
"I played for Italy with Roberto a number of times - but it is not just about me, this will be a very exciting trip for the players and a great reward for our fans," he said.
"No matter what the result or what happens on the day it will be a very good test for my players. We will experience football at a completely different level and this will be an excellent challenge and motivation for us.
"It's a very exciting moment for Watford. I think I am most of all pleased for our supporters to have this chance to follow us to a great stadium and to the Premier League champions.
"It is our fans who have been right behind us, so they deserve to enjoy such an occasion as this.
"They say the FA Cup is unpredictable. We must hope this is the case when we are in Manchester. It will be an honour to play one of the best teams in the country, and we will want to do Watford proud."