The Gers have been in pursuit all summer, but Celtic have now reportedly formalised their interest.
Rangers have been on the playmaker’s tail for several months - with three bids reportedly being rejected – but now face being blown out of the water by the SPL champions.
The report confirms that negotiations for the Scottish Championship player of the season - valued at around £1 million - have been opened by Celtic, but that no fee has been agreed as yet.
The Hoops would now appear to be favourites for his signature due to a number of factors. Aside from being able to offer Allan greater financial incentives, top flight and European football – the Hoops also stand to benefit from Hibs’ reluctance to sell their key man to their main promotion rival.
Celtic also have Dylan McGeouch as a bargaining chip and could use him in any potential deal, after the 22-year old enjoyed a fruitful loan spell at Easter Road last season.
Rangers are sure to be incensed by Celtic's late swoop and the Ibrox club's needs are arguably the greater of the two. Celtic boast a fine batch of attacking midfielders and have good cover across the front four, while the capture of Allan for Rangers could be the difference between a league title or another year in the Championship.