Celtic midfielder Stuart Armstrong has joined Southampton on a four-year deal after a fee of around £7m was agreed.

The Scotland international becomes Saints boss Mark Hughes' first signing since he took over on the south coast towards the end of last season.

Armstrong is the latest player to move from Parkhead for St Mary's, after Virgil Van Dijk and Victor Wanyama also made the same switch in recent seasons.

Southampton manager Mark Hughes said: "Stuart is a player who we have admired for some time, and I am delighted we have been able to bring him here, especially given the competition we faced to sign him.

"He brings with him extensive experience of European football and has developed his game impressively over the past few seasons at a major club in Celtic, where there is a demand not only to perform but also to win. Stuart has done both during his time there.

"Our research tells us he is an excellent young man, intelligent, and a strong team player, and clearly having another really good character in our group is part of what we want here at Southampton."

The 26-year-old played a starring role for Celtic as they marched to the treble during Brendan Rodgers' first season in charge.

But injuries restricted his game time last season while Scott Brown, Callum McGregor and new signing Olivier Ntcham impressed at the heart of the champions' midfield.

With 12 months to run on his Hoops deal, Armstrong was linked with a host of clubs but it is the Saints who have won the race for his signature.