The ruthless oil tycoon will be murdered in a new whodunnit plot, following the death of actor Larry Hagman back in November.
[Larry Hagman with the cast of 'Dallas']
"JR was such a delicious and iconic character that we couldn't just kill him by natural circumstances," Cidre told TV Guide of the plotline.
"It had to be bigger than that, and more fun than that, and at the same time, it has to be emotional and a proper goodbye to both JR Ewing and Larry Hagman."
The eighth episode of Dallas season two is expected to feature JR's funeral, with a number of former Dallas stars returning to the show to pay their respects.
[Larry Hagman, Linda Gray and Patrick Duffy]
"A little bit of [the whodunnit mystery] will be revealed in episode eight, and then we will take the rest of the season to reveal [the rest]," Cidre explained.
Cidre previously admitted that she had started "crying so hard" when writing the funeral episode, while Dallas star Patrick Duffy (Bobby Ewing) has insisted that his late co-star Hagman will be given a "sensitive" send-off.
Dallas continues on TNT on Monday nights and airs on Channel 5 in the UK the following day.
> Six Million Dollar Man Lee Majors joining Dallas
Watch a promo for season two of Dallas below: