It's fair to say that John Guidetti has been Ronny Deila's best signing so far.
Needing a striker on deadline day, Deila managed to use his connections at Manchester City to grab Guidetti on loan for the season, and he's close to replicating the form he showed during a loan spell with Feyenoord in 2011-12.
The Swede smashed 20 goals in 23 games for the Dutch side, and has so far hit ten goals in 11 games for Celtic, underlining his goalscoring prowess.
The 22-year-old is only on loan though, and whilst reports have speculated that Celtic will look to tie up a permanent deal in January, he is still of course owned by Manchester City.
Now, City star James Milner has revealed that he is in contact with the centre forward, but admitted that he needs to make sure he keeps his feet on the ground.
"John’s a great character but he can get carried away so we have to bring him down and give him a hammering," said Milner. "We’ve told him to calm his celebrations down. But he’s a great character, he’s scoring a lot of goals and I’m sure he’ll get plenty more."
Yet with rumours over a permanent stay in Glasgow, Milner also admitted that he doesn't know whether the striker will return.
"I don’t know what John is thinking, what he wants or if he’d get games if he comes back to City. He has a scored a lot of goals in two loan spells. I knew he would do well at Celtic because he’s a goalscorer and a bubbly character."
"It will be up to John in the end. He wants football and needs it at his age. There’s a lot of quality at City and it’s hard to get into the team so the younger lads need to go out on loan." he added.