The 23-year-old, who has six caps for his country, has joined on loan allegedly with a purchase option set at €15 million for the remainder of the 2024/25 Premier League season.
On joining Southampton, Albert Grønbæk said: “I’m just so excited. It’s a big club and I think the playing style is suiting me very well, so I’m just very pleased to be here.
“The facilities are very good and the stadium looks incredible. It’s even bigger and better when you come in person, so I’m just so excited to play there. I’m proud to be here.”
Grønbæk began his professional career with AGF Aarhus in Denmark, before signing for Bodø/Glimt in 2022 where he won two Norwegian league titles and scored an impressive 30 goals in 87 appearances in all competitions, including the UEFA Europa League.
Having scored eight gols in 16 games at the start of the following season, he signed for Rennes making his senior debut for Denmark in September and scoring against Serbia in his second international.
Grønbæk had a bright start to his career at Rennes but suddenly the club found itself in a long-lasting slump which continued even though Jorge Sampaoli took over from Julien Stéphan and on 17 January Sampaoli said that Grønbæk had not settled in the French club and wanted a change.