Arsenal Complete £25m Signing Of Kieran Tierney

Arsenal have completed a £25million deal for Celtic defender Kieran Tierney, with the left back signing a five-year deal at the Emirates.

The Gunners have been chasing Tierney's signature all summer and saw two bids rejected before eventually meeting Celtic's valuation on Wednesday.

Tierney, who will wear the No 3 shirt, underwent a medical at the club's LondonColney training ground on Thursday before putting pen to paper just hours before the transfer deadline.

Tierney told www.arsenal.com: 'It was the hardest decision in my whole life that I've had to make.

'I had to speak to my family and my close friends and my agent as well because it's a hard decision to leave a club that you love so much. People need to know that as well.

'I feel Arsenal is a massive club and it's a great opportunity for me as well. I'm delighted to be here.

'When I was younger, it was always Celtic. The ambition was Celtic and that was my dream when I was younger. But when you get older... I've done that, I've made my dream, I've lived my dream and I've loved every single minute of it.

'Now I just feel was the right time to take a step on. I feel this is a great opportunity for me.'

The 22-year-old is regarded as one of Britain's brightest young talents having made his Celtic debut as a 17-year-old back in April 2015.

He has since gone on to make 171 appearances for the reigning Scottish champions, scoring eight goals and making 37 assists.

The full back leaves the club he supported as a boy as they close in on Rangers' nine successive titles, having already won eight - including three straight domestic Trebles.

Tierney has also become an integral part of the Scottish national team squad, and has so far accumulated 12 caps.     

His arrival at the Emirates is a big boost to an Arsenal defence that conceded 51 goals in the Premier League last season but he is unlikely to feature in their opening day clash against Newcastle on Sunday. 

The defender underwent a double hernia operation at the end of last season and has been unable to resume full training after complaining of pain in his groin.

Meanwhile, Arsenal are hopeful of bolstering their defence further with the surprise £8 million signing of David Luiz from Chelsea.

The centre-back was a regular under Maurizio Sarri last season but reportedly told new boss Frank Lampard of his desire to join the Gunners on Wednesday.

The two clubs are now in negotiations, with the Gunners hopeful of concluding negotiations before Thursday's 5pm deadline.