The midfielder, 18, has agreed to move down south to join the London club from January 1 next year. Kelly had been wanted by Celtic to sign a new contract at Parkhead but talks had stalled over a new deal for the highly-rated prospect. Reports suggested a four-year deal was knocked back by Kelly – who made his debut for Celtic in January. He played six times for the first-team. Now, Millwall manager Neil Harris has confirmed Kelly will leave Celtic in January to head down south.

He (Kelly) is a very good player. When Dan first walks into the building he is not going to be someone that everyone should expect to go straight into the team.

He (Kelly) is a very good player. When Dan first walks into the building he is not going to be someone that everyone should expect to go straight into the team.

“He is very young but everyone should take heart that they’ve seen Alfie Massey make his debut tonight and it was an outstanding performance. Dan is a box-to-box midfielder, probably an old-fashioned eight, who has great energy. I’d liken him to a young George Saville when he first came into the football club – breaks into the box and scores goals.

“He is very young but everyone should take heart that they’ve seen Alfie Massey make his debut tonight and it was an outstanding performance. Dan is a box-to-box midfielder, probably an old-fashioned eight, who has great energy. I’d liken him to a young George Saville when he first came into the football club – breaks into the box and scores goals.

Kelly had been wanted by Celtic to sign a new contract at Parkhead but talks had stalled over a new deal for the highly-rated prospect.

Reports suggested a four-year deal was knocked back by Kelly – who made his debut for Celtic in January. He played six times for the first-team.

Now, Millwall manager Neil Harris has confirmed Kelly will leave Celtic in January to head down south.

He is very young but everyone should take heart that they’ve seen Alfie Massey make his debut tonight and it was an outstanding performance. Dan is a box-to-box midfielder, probably an old-fashioned eight, who has great energy. I’d liken him to a young George Saville when he first came into the football club – breaks into the box and scores goals.

“He has got passion and real