'It's done boys!' - Kieran Tierney poses for photo with Arsenal fan ahead of £25m transfer from Celtic

Kieran Tierney in action for Celtic. The defender is on the cusp of completing a move to Arsenal

The 22-year-old was assessed by Arsenal's medical staff today and is expected to become the most expensive Scottish player in history when he completes his move to the Emirates ahead of this afternoon's 5pm English Premier League transfer deadline.

A Gunners fan, Paul Moody, was on hand to take a picture with the Scotland international immediately after his medical, captioning the snap: "It's done boys! Welcome to the Arsenal Kieran."

Moody later told the Press Association that he had met the player at a hotel near London Colney, adding: "He signed a shirt for me and all he said was 'I can't have a photo with the Arsenal shirt in it as it's not been announced yet'."

The left-back is understood to have flown down to London last night before his medical this morning and is set to strike a £75,000-a-week move to Unai Emery's side.

The Hoops are likely to benefit from a large sell-on clause, with the all-in deal trumping Moussa Dembele's £20 million move to French side Lyon last summer.

Tierney has made more than 150 appearances for Celtic since breaking into the team in April 2015. He has won eight major trophies with the side and was part of the two treble-winning teams.

The Isle of Man-born defender will have to wait to make his bow in an Arsenal shirt as he continues his recovery from double hernia surgery and osteitis pubis.

Reports this week claimed Tierney would be out for around eight weeks but Celtic manager Neil Lennon believes the player is around a week away from returning to full training and a further seven days from a comeback on the pitch.

Brazilian defender David Luiz is also in line to join the Gunners from Chelsea in a £8 million move and could line up alongside Tierney in a new-look Arsenal defence as Emery looks to solve his defensive woes. Arsenal conceded 51 goals last season - only Manchester United (54) and West Ham (56) let in more goals in the English Premier League top ten.