The defender came through the youth ranks with the Hoops and enjoyed a spell as first-team captain before his departure for Middlesbrough in 2010. Now back in Scotland after penning a one-year deal with the Steelmen earlier this week, McManus will find himself up against his old side on October 5 at Parkhead.
He said: "It will probably be the strangest part of my career. I spent 12 years at the club. Everybody knows it was a massive part of my life and still is. I had some wonderful times there. It will be strange but I'm a Motherwell player now and I need to do my best for Motherwell and that's what I will try to do."
McManus opted for the move to Motherwell after also training with fellow Scottish Premier League side Hibernian.
He said: "I was hoping either to go to Hibs or come to Motherwell. I enjoyed Hibs - they were good people, with good facilities - and I came here and felt the same.
"It was a tough decision to be honest. Hibs were terrific but I went with my gut feeling, which was to come here. The manager didn't need to sell the club. I know what it's all about here and I'm looking forward to the challenge."
McManus knows the SPL he is returning to this season is very different from the one he left three years ago.
He said: "There are a lot of younger kids coming through now. Scottish football gets a lot of negative press, especially down south, where it gets hammered to be honest. But it gave me the platform to go on and have a successful career so I would never belittle it. I'm looking forward to playing in it again."
Despite his decision to return to his homeland, the 30-year-old was not disappointed by how his spell in England turned out.
He said: "I had three-and-a-half good years and I really enjoyed my time at Middlesbrough. Tony Mowbray was great with me. When I left Celtic, it was well documented that we didn't have a good relationship at all. When I went down there, it was completely different.
"He never saw me as being a player he could rely on week in, week out, which is fine, but as a man and as a coach he was first class with me. I met some really good people at Middlesbrough. It's a really good club and the fans were terrific with me and I loved my time down there.
"The hardest part, especially in the last year, was my wife and kids being up the road and me not living with them. I knew the time was right to move on."
McManus is now hoping a successful season with Motherwell could lead to a recall to the Scotland squad, having last featured for the national team in October 2010.
He said: "I'm only 30 and everybody knows the relationship I've got with Gordon Strachan, which is pretty good. But you don't get any favours in football, you only get what you deserve.
"If I end up back in the Scotland team, then great. My aim is just to concentrate on playing week in, week out here and doing well and see where it takes us."
- Sports & Recreation