The news was confirmed via Heerenveen's Twitter account on Tuesday:
Marca (via The Sun's Matt Heath-Smith) reported he will move to the Dutch top-flight side until the end of next season.
Per Carlos Forjanes in AS, it has long been expected that the 18-year-old would spend some time away from Real, with the Bundesliga previously seen as the best place for him to thrive.
But the Norway international has now moved to Heerenveen, and he will likely be given more opportunities to play first-team football in the Eredivisie, which should allow him to improve and start to fulfil his huge potential.
Madrid-based football writer Thore Haugstad provided Odegaard's Real stats and expressed excitement at the move:
Odegaard is widely regarded as one of the brightest young talents in European football, and he moved to Los Blancos from Stromsgodset in January 2015 having been courted by the likes of Bayern Munich and Barcelona.
It was initially reported that the youngster struggled to integrate himself with the Real Madrid Castilla side, because of his huge €100,000-per-week salary, per Sport.
Meanwhile, Odegaard's former mental coach Klaus Pettersen questioned his long-term future at the Santiago Bernabeu, per Kristan Heneage for Goal.
A move away from Madrid should benefit Odegaard as the pressure on him will be relieved, and he will have more opportunities to improve his play.