Martin O'Neill welcomed a "hungry" Alex Oxlade-Chamberlain to Celtic after the 32-year-old midfielder joined the Scottish side until the summer, with an option for a further year.
The former Arsenal and Liverpool player has been a free agent since leaving Turkish side Besiktas in August.
Capped 35 times for England, Oxlade-Chamberlain has been training with Arsenal but on Friday, O'Neill revealed the player would be arriving in Glasgow on Saturday for a medical.
The move is subject to international clearance but ahead of the Scottish Cup tie against Dundee at Celtic Park, O'Neill told the club's official website: "We are really pleased to bring Alex to Celtic.
"He still has so much to offer the game, and I am sure he can add another dimension to us with his great ability and wealth of experience in the game.
"Above all, he is passionate and excited about this move himself so we are welcoming a great player who is hungry to help us achieve as much as we can."
Oxlade-Chamberlain, speaking to Celtic TV, revealed his excitement at moving to the east end of Glasgow.
He said: "It's been a busy few days but I'm delighted and really excited.
"Speaking with the manager, it just felt like the perfect fit for me and I feel like I can come in and help out the lads.
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"Just talking to the manager, and Shaun Maloney [nterim assistant manager] as well, who told the expectations on the club and what it means to play here, what our targets are and that he's going to push me.
"That's all the stuff I identify with and that's the environment I've always been in and been lucky enough to be in.
"It's exactly what I need. I need another challenge and lucky enough at a massive club like this.
"And they can help me get back to where I need to get to and, more importantly, I need to help the team achieve the goals we want to do."
