Michael Obafemi has signed a new three-and-a-half-year contract with Southampton.
The 18-year-old Academy graduate put pen to paper on the deal, which runs until 2022, on Wednesday.
He made his senior debut as a 17-year-old at home to Tottenham Hotspur, in January 2018 – becoming the second-youngest player to feature for the club in the Premier League.
A prolific scorer for both the Under-23s and Under-18s, the forward netted his first senior goal in December's 3-1 win at Huddersfield, and has now made seven first-team appearances for the club.
He made his senior debut for Republic of Ireland this season against Denmark in Martin O'Neill's final game.
Obafemi said: "It's a good day. I'm happy that it's done and now I'm looking to move forward.
"I'll always be thankful to the club for sticking by me, and I just want to show everyone what I've got.
"I'm determined to show the fans and everyone at the club why I've been given a three-and-a-half-year deal."
Manager Ralph Hasenhüttl said it is a big moment for Obafemi: "Young players like Michael represent a big part of the future of Southampton, so this is an important day for him and also for the club.
"Already, he has shown to me he can have a big impact in our games and, with the right guidance and also with the right approach from him, I think this influence will increase.
"This is a big day for Michael, but I think what is most important now is that he realises this is the start for him, and that he must use this as a base to make the next steps in his development.
"There is still a great amount of potential for Michael to fulfil and a lot for him to achieve, and this is the best place for him to do it, so he must focus on working as hard and professionally as possible to make sure he becomes the player I believe he can be."