Huddersfield have signed centre-half Murray Wallace and striker Kallum Higginbotham from Scottish First Division side Falkirk.
Wallace, 19, made his Bairns debut in August and has since made 22 starts for Steven Pressley's side.
The initial fee is £300,000 rising to £700,000 and he will play for Falkirk on loan until the end of the season.
Higginbotham, 22, began his career at Oldham and moves from Falkirk for what the Bairns say is a "six-figure sum".
His deal at Huddersfield does not involve a loan back to the club.
Falkirk manager Steven Pressley told the Bairns website: "Murray has been fantastic for us but it is not the parting of the ways as the deal means he will remain at Falkirk till the end of the season.
"It is an excellent bit of business by the club - with add-ons, it could mount up to quite a substantial figure over time.
"Obviously we will miss him when he eventually goes as he is a terrific young player. However, this is part of our long-term Academy strategy and we are comfortable with the move."
Meanwhile, Falkirk have turned down an offer from Blackpool for their midfielder Mark Millar.
A club spokesman said: "The offer came nowhere near our valuation of the player and, for this reason, Blackpool's bid has been turned down."