The Scottish champions have been pitted against the four-time European champions as well as Portuguese giants Benfica and Russian outfit Spartak Moscow in Group G.
"We're familiar with the three teams," said Lennon. "Obviously, we've had history with all three of those teams.
"If I remember correctly, certainly under [former manager] Gordon [Strachan] we played Barcelona and Benfica and we also knocked out Moscow in the playoffs, so it's a tough, tough group.
"But I think all the teams play good football so it should be quite attractive to watch."
However, Lennon refused to be complacent when asked about Celtic's chances of progressing to the round of 16 from the group.
"Let's not get carried away, let's take it as it comes and see where we are first and what fixtures come up," he said.
"Listen, we're in it now. It's fantastic to be here. We're going to make the most of it and enjoy it.
"I'm delighted to be here, it's just fantastic being in the draw."
Celtic are in Scottish Premier League action on Saturday when they host Hibernian.