The bout was confirmed when the promotion revealed the current poster for WSOF 26 on Wednesday.
Spong (2-0) is one of the most seasoned out there, having competed in MMA, boxing and kickboxing. He has had almost 100 professional kickboxing bouts, and has only fought two boxing bouts since suffering a horrific leg injury in the Glory ring when he fought Gokhan Saki in early 2014. Both his professional MMA victories have taken place in the WSOF cage.
Heun (8-4) is a veteran of two seasons of The Ultimate Fighter. He is coming off a submission win over Davin Clark at WSOF 22, this is his sole victory since being submitted by Clifford Starks at WSOF 19.