Hoops boss Neil Lennon confirmed this morning that Hooper had completed the formalities of his move from Scunthorpe, with the striker just making it in time for the plane for the third qualifying round first leg against Braga.
The 22-year-old is almost certain not to start tomorrow due to a lack of game time but he could yet make his bow from the bench.
"I can play, yeah, but I haven't played one game yet in pre-season," said Hooper, who admitted he was not yet match-fit.
"I've trained hard - I didn't want to get injured for a big move.
"So I hope the gaffer will give me a part of the game."
Asked whether his stomach had been doing somersaults over the prospect of joining Celtic, Hooper said: "It's doing somersaults now."
He added: "It's been a busy last few days. I signed yesterday morning, had a medical that went on until last night, 8pm, and nearly didn't travel with the team today."
Having begun his career as a teenager outside the English Football League, Hooper has managed to make his mark at every level up to the Championship.
But he acknowledged his latest career move would be his biggest hurdle yet.
"It's a massive step up from the Championship, the lower Championship, to the Champions League, SPL," he said.
"I've just got to show the team, show the gaffer, what I can do."
Hooper has been inundated with messages from wellwishers since completing his move.
Asked what his family and friends had said to him, he replied: "Everything. 'Congratulations', 'All the best', and, 'Score a goal in the Champions League'.
"I've had loads of phone calls, loads of texts about it, and they're all wishing me good luck."
Hooper was confident he would be ready for the goldfish bowl of life as an Old Firm footballer.
"Everyone wants to have a bit of pressure playing football and I'm looking forward to it," he said.
One new team-mate with a wealth of experience at dealing with such hazards - not always successfully - is Scott Brown.
Hooper is looking forward to the Scotland midfielder providing the ammunition for him to fire in the goals at Parkhead.
"There are good players, especially the captain," Hooper said.
"He's one of those who can do anything."
Fans eager to buy a replica shirt bearing the number of their new signing may have to pay a few extra pounds, with Hooper opting to sport 88 on the back of his jersey.
He explained: "It's my lucky number and the year I was born - and the club was founded in 1888."