Celtic are hopeful of adding Kristoffer Ajer to their list of star players signed up to lucrative new contracts ahead of the January window, Football Insider understands.

The Hoops have announced agreements with Callum McGregor, James Forrest and Scott Bain in the last week as part of a concerted effort to keep their key men.

A Celtic source has told Football Insider that the club are also making progress in tying Ajer down to a new deal after offering him a deal worth around £25,000-a-week.

Talks are well underway and there is hope a breakthrough is in sight to finalise the deal before the winter window opens for business.

Celtic are aware of interest from their giant centre-back from leading European clubs, with Serie A giants AC Milan among those linked with him during the summer.

He has developed impressively over the last 12 months and is firmly established as a first choice in Neil Lennon’s title chasers alongside £7million summer signing Christopher Julien.

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Ajer has already clocked up a mammoth 23 appearances for Celtic this season, even filling in at right-back earlier in the campaign before a slew of new arrivals in that position.

Since signing for Celtic in January 2016, the Norway international has made 103 appearances for the club and provided excellent value for the £550,000 transfer fee.

Ajer signed a new four-year deal in May of last year that runs until the summer of 2022, but Hoops chiefs recognise he deserves recognition for his status as a key first-team player.

In other Celtic news, it can be REVEALED that the club have agreed the terms of a sensational £8million deal.