Southampton have signed Celtic midfielder Stuart Armstrong on a four-year-deal, understood to be worth £7m.
The 26-year-old, who has made six appearances for Scotland, joined Celtic in 2015 from Dundee United.
He scored 28 goals in three seasons with Celtic, with 17 of those coming in his first season under Brendan Rodgers.
"Our research tells us he is an excellent young man - intelligent, and a strong team player," Southampton boss Mark Hughes said.
"He has shown tremendous drive to improve and has also displayed a great desire to be a part of what we are trying to achieve here."
Armstrong has won four Scottish Premiership titles, two Scottish Cups and two Scottish League Cups.
"It is important we add a greater goal threat to the team as a whole, and Stuart's record of scoring and creating makes him an extremely exciting addition in that area," Hughes added.
Southampton finished 17th in the Premier League last season and narrowly avoided relegation.
They begin the 2018-19 season with a home tie against Burnley on 11 August.
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