Tottenham manager Mauricio Pochettino has said the club will trigger an extension clause in Toby Alderweireld's contract.
The Belgium defender will now be contracted to Spurs until the summer of 2020, having been due to be a free agent at the end of the season.
However, by taking up the year's option it also activates a £25million release clause which runs from the start of the 2019 summer transfer window to the last two weeks.
The news comes several weeks after Spurs also triggered an option on Alderweireld's Belgium team-mate and close friend Jan Vertonghen's contract.
Pochettino said: "Yes, for sure. It is obvious. It is the same situation as Jan (Vertonghen)."
Alderweireld was expected to leave last summer as Spurs looked to cash in on him after he reportedly rejected a new long-term deal.
The 29-year-old barely played at the back end of last season, despite being fit after a hamstring injury, as Pochettino appeared to freeze him out.
He was reportedly on Manchester United's radar for much of the summer, but no deal happened and he has enjoyed a second coming at Spurs this season.
While Vertonghen and Davinson Sanchez have struggled with injuries this term, Alderweireld has been a mainstay of the side, making 24 appearances.
He has been an important player as Spurs have made themselves Premier League contenders, with the 5-0 win over Bournemouth on Boxing Day taking them above Manchester City into second.
They are fighting in four competitions, with the FA Cup starting next weekend, and have endured a packed fixture schedule with an injury-hit squad.
But such is Spurs' momentum at the minute – they have won 12 of their last 14 games in all competitions – that players are desperate to get out on the pitch.
Dele Alli is one of those after he missed the Bournemouth game with a hamstring injury and he will be assessed ahead of Saturday's clash with Wolves at Wembley.
Pochettino said. "Sometimes for us it's so tough to discover the real state and level of the players. But of course that is a very good signal for us, that all the players want to play, no-one wants to rest.
"Dele yesterday was involved in the squad but after was out of the 18. But this morning he said to me, 'Gaffer I'm going to be ready'.
"I said, 'Relax, you need to train this morning and then we'll see tomorrow and assess you'.
"But that is a very good signal, that all the players want to be involved. That increases the level, the competitive level in the squad and for sure helps to get good results."
With the January transfer window around the corner there will be plenty of focus on whether Spurs make any signings, given they did not do so in the summer.
But Pochettino says any incomings might have to be preceded by outgoings.
He added: "It depends on players out and then we're going to see if we can add some quality to help the team.
"But I think it's not going to be easy to add players in January. For sure it's going to be tough to add.
"Until the market is open it's difficult to talk because now we have a lot of games to play. But for sure in January when the market is going to be open that's the moment when we're going to talk with different players – players that maybe come to talk with us because they want to leave or they want to play more."
