As well as the Catalan giants, the Hoops will also face Benfica and Spartak Moscow in Group G as they bid to progress on the European stage.
But, rather than fear the challenges which lie ahead, youngster Watt is relishing the prospect of facing some of the best players in the world. He said: "Barcelona are the best team in the world, but Benfica and Spartak are beatable. At home, even Barcelona are beatable."
The teenager, who was named Clydesdale Bank Premier League young player of the month for August, added: "I know people think that's unrealistic, but you never know with Celtic at Parkhead - it's just a different level.
"It's a massive club and we've got a good, young set of players. Hopefully we can take that on to the park and get a few results and qualify for the last 16.
"In the home games in the Champions League, the roar is just unbelievable, with 60,000 fans going mental.
"It's unbelievable, there is nothing like it. Even just being on the bench for the last game and coming on and hearing the fans singing was like a different world."