Nathan Redmond has signed a new four-year contract with Southampton until 2023.
The 25-year-old was voted the club's player of the season by both his team-mates and Saints supporters in 2018/19 after scoring nine goals in the final six months of the campaign.
"I'm really happy to have signed and I'm just wanting to get the season up and going now," said Redmond, who moved to St Mary's from Norwich in 2016.
"We've got a great group of players here who I've been with for the last three years. I see them every single day and it's a pleasure to go out there and perform with them at the weekend and train hard with them every single week.
"I feel like we can hopefully build something special and to be a part of it for the next four years is good for me."
Southampton manager Ralph Hasenhuttl added: "It is very good news for the club. He's a player who showed in the last season that he is very important for Southampton and I think it's a massive signal for the club, and for us all, that he wants to follow our way.
"It's a very positive day for us."