The 19-year-old Israeli attacker’s transfer was completed on Wednesday afternoon as he put pen to paper on a five-year deal.
He moves from Maccabi Petah Tikva for a reported fee of £3.5 million and will be expected to push for a regular first-team place under new boss Ange Postecoglou at Celtic Park this season.
Having made his international debut for Israel this summer, Adaba insists he’s ready to hit the ground running for his new employers as he spoke of his wonder at joining such “a huge club”.
He told the Celtic website: “It feels amazing to sign for a club like Celtic. This is a huge club and it's an honour. I know the fans are incredible. I have watched some Celtic games in Israel so I know how amazing these fans are and how special this stadium is. I can’t wait to get out on the pitch to play and help my teammates bring more success to the club.
“I’m looking forward to meeting my teammates and the manager. I have heard great things about the facilities at Lennoxtown so I’m excited to get out on the training pitch and get down to work.”
Pre-season for me has been good. I was playing international football and have been training in pre-season so I am feeling good and ready to play. I know there are important games very soon so I will be ready if the manager calls on me.
“My main aim to help the team win the title. That’s my focus and I will give everything I have in training and out on the pitch to help the club achieve this.”
Adaba becomes Celtic's fourth signing of the summer alongside fellow fresh-faced new recruits in the form of 18-year-old Scunthorpe United attacker Joey Dawson, and Sheffield Wednesday pair Liam Shaw and Osaze Urhoghide.
Though he doesn't turn 20 until October, the versatile forward played over 70 times in the Israeli top flight for Petah Tikva, who finished fifth in the table last term.