Armstrong, 24, was the second-highest scorer in the division, scoring 28 goals for Blackburn during the Sky Bet Championship 2020-21 campaign. His arrival comes after Southampton sold Danny Ings, the club's top goalscorer last season, to Aston Villa for PS25m last week. Armstrong stated, "It's incredible to be here – such a huge club with a great support base and it's just what I'm looking forward to," "I felt it was the perfect step for me." "I wanted to return to the Premier League after what I did for Blackburn. I'm thrilled." Armstrong, who was previously capped five times at England's Under-21 level, started his career with Newcastle. He had loan spells with Coventry and Barnsley before moving to Rovers in 2018. Ralph Hasenhuttl, Southampton manager, said that Adam was a major target for the club this summer. He was also very interested in other clubs. He is at an ideal stage in his career to be here. He is a dynamic, young player who has shown great potential and has already had a good experience. "He will bring many qualities to our team and give us another option in attack, which is important for us." Southampton signed 19-year-old striker Armando Borja on a season-long loan from Chelsea earlier in the day.