Southampton have signed Scotland international Stuart Armstrong from Celtic on a four-year deal for a reported £7 million.
The midfielder was beset by injuries last season, one year after scoring 17 goals.
He is the Premier League club's first signing of the summer.
"Southampton seems a really good fit for me," Armstrong said in a statement. "Watching from afar, I really enjoy the attractive football that they play and I'm very happy to be here."
#SaintsFC is delighted to announce the signing of attacking midfielder Stuart Armstrong from @CelticFC: https://t.co/Z5uX8fSQDV
— Southampton FC (@SouthamptonFC) June 26, 2018
Southampton narrowly avoided relegation last season under Mark Hughes, who replaced Mauricio Pellegrino in March.
"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," Hughes said in the statement. " ... It is important we add a greater goal threat to the team as a whole, and to our midfield specifically, and Stuart's record of scoring and creating makes him an extremely exciting addition in that area."