The fee is thought to be £12m up front with a further £2m of bonuses payable against appearances and Huddersfield remaining in the Premier League.
The Terriers are currently four points clear of the relegation places in 11th, surpassing many pundits expectations for the first half of the season.
Head coach David Wagner’s jig around the Christmas tree in a video which went viral on social media reflected the feelgood factor around the club at the moment.
Pritchard’s arrival underlines the determination of the board to back the squad’s efforts so far and not settle just for survival.
The former Tottenham player followed a well-trodden path from White Hart Lane to Carrow Road in a £8m deal in 2016. Since then, he has scored seven goals in his 38 appearances for the club, registering his first strike of the season in the 2 – 0 win over Birmingham City on Boxing Day.
Pritchard’s only previous venture into the Premier League was an unsuccessful loan spell with West Bromwich Albion where he played a total of 62 minutes during the 2015/16 season.
He managed two substitute appearances for Tottenham (12 minutes), after which he headed off to Peterborough, Swindon and Brentford on loan.