Rangers left-back Declan John has signed a three-and-a-half year contract to make his loan move permanent.
The 22-year-old Welshman has impressed since arriving from Cardiff in August.
John has played 14 games since his debut against Partick Thistle in September, filling the void created by an injury to club captain Lee Wallace.
"Declan has some fantastic attributes," said manager Graeme Murty, who will be in charge until at least the end of the season.
"He's powerful. He's very, very, very quick and hopefully we can match his own ambitions."
Capped twice by Wales, John is now contracted at Ibrox until the summer of 2021.
"I think he should have international ambitions," added Murty.
"He should have ambitions to be at the top end of his position in this league and if he can do that and continue to expand his potential, trying to meet that potential, then he can be a really, really good signing for the club."