The 19-year-old Dane has made nine Championship appearances this season.
He scored his first career goal in the 2-0 win at Nottingham Forest in February.
Town boss David Wagner told the club website: "We are proud he is our player. He has taken his opportunity in the team recently, showing he can bring his performance to the pitch."

Teleperformance provides outsourced customer service for well-known brands and government organisations.
The jobs will be created by 2018 and will generate ??12m in salaries for the local economy.
They will have an average salary of ??14,700.  Invest NI is offering financial backing of ??2.5m.
The Department for Employment and Learning (DEL) offered ??249,500 worth of support with pre-employment training for 100 people.
Teleperformance opened its first call centre in Bangor in 1998 and now has 182,000 employees across 270 centres in 62 countries.
It currently employs nearly 2,000 people in Bangor and Newry.
Finance Minister Arlene Foster said the reinvestment by Teleperformance was "a significant endorsement for Northern Ireland".
"The job opportunities created will not only benefit people in Enniskillen but also those in the surrounding areas," she said.
"There will be a wide variety of roles appealing to those looking to develop their career, and those looking to return to work.
"There will also be opportunities for young people, who will benefit greatly from training and skills development as they begin their working career."
Alistair Niederer of Teleperformance said the firm was delighted to be "growing its presence" in Northern Ireland.
"It is our philosophy to transform passion into excellence and Northern Ireland had proven to be a great place for us to do this," he added.
Employment and Learning Minister Stephen Farry said the new jobs would "provide a variety of opportunities, offering flexible meaningful employment in a range of positions and the opportunity to develop important, transferable skills".

Malik said: "My life with One Direction has been more than I could ever have imagined. But, after five years, I feel like it is now the right time for me to leave the band.
"I'd like to apologise to the fans if I've let anyone down, but I have to do what feels right."
One Direction will continue their world tour as a four piece and record a fifth album later this year.
Last week, Malik walked away from the band's world tour after being signed off with stress.
He returned to the UK shortly after being forced to defend his relationship with his fiancee, Little Mix singer Perrie Edwards.
A photo had earlier emerged of him holding another woman around the waist.
A second photo, taken from behind, showed Malik standing close to the woman. Their hands and arms looked as though they were linked.
In a statement, the rest of the group said: "We're really sad to see Zayn go, but we totally respect his decision and send him all our love for the future.
"The past five years have been beyond amazing - we've gone through so much together, so we will always be friends.
"The four of us will now continue. We're looking forward to recording the new album and seeing all the fans on the next stage of the world tour."
Simon Cowell, who discovered the boyband on talent show The X Factor, said: "I would like to say thank you to Zayn for everything he has done for One Direction.
"Since I first met Zayn in 2010, I have grown very, very fond - and immensely proud - of him. I have seen him grow in confidence and I am truly sorry to see him leave.
"As for One Direction, fans can rest assured that Niall, Liam, Harry and Louis are hugely excited about the future of the band."
Niall Horan, Liam Payne, Harry Styles and Louis Tomlinson signed with Simon Cowell's record label Syco Records in 2010 after finishing third on The X Factor.
Zayn's had a tumultuous time with the band and almost quit during bootcamp.
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Huddersfield Town midfielder Philip Billing has signed a contract extension until the end of the 2019-20 season.
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A call centre company is to create 800 new jobs in Enniskillen, County Fermanagh.
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Zayn Malik has quit One Direction, the band have confirmed in a statement.