The bout isn't yet set though has apparently been ordered by the WBO.
Although arrangements for the bout are yet to be made Onesongchai have said that they expect the bout to take place in either Thailand or Australia in May. At the moment the parties are free to negotiate between themselves though purse are looming if no deal can be reached between the two sides.
The idea seems to be that the winner of Chonlatarn, the WBO #2, and Brunker, the WBO #4, will face the winner of the up coming WBO world title fight between Gary Russell Jr, the WBO #1, and Vasyl Lomachenko, the WBO #5.
(Image courtesy of http://www.onesongchai.com/)