Burnley broke their transfer record to recruit Robbie Brady from Norwich on transfer deadline day.
The Republic of Ireland international signed a three-and-a-half-year deal at Turf Moor for an undisclosed fee.
But the Clarets confirmed the sum paid eclipsed the £10.5million they paid Derby for Jeff Hendrick last summer.
Brady spent 18 months at Norwich, having joined from Hull for £7million, and was part of the team relegated from the Premier League last season.
He was the second new arrival at Burnley on Tuesday with Sean Dyche also signing Ashley Westwood from Aston Villa.
Burnley were one of the busier sides in the Premier League in an otherwise quiet deadline day although Odion Ighalo completed one of the other biggest deals after leaving Watford for China.
The striker joined Chinese Super League club Changchun Yatai for an undisclosed fee, although it was reported to be around £20million.
Ighalo was also linked with a move to West Brom but that would only have been as part of a swap for Saido Berahino, who did not want to move to Watford.
The Baggies were not keen to buy the Nigerian striker, who has not scored in 15 games, outright.