ODowd will also appear in the series, Moone Boy, playing the imaginary friend of the lead character Martin an 11-year-old growing up in a rural Irish town in the late 80s.
The series is partly-autobiographical, with part of it being shot in the County Roscommon town of Boyle, where ODowd grew up. It will also feature animated sequences to illustrate Martins dreams.
The Bridesmaids actor co-wrote the six episodes with Nick Murphy with the idea coming from the short film he made for Sky1's Little Cracker seasons last Christmas.
Filming will take in the new year, for broadcast next summer, and it is being made by Coogans Baby Cow and Stephen Frys Sprout Pictures. The lead role has not yet been cast.
ODowd is also writing a pilot comedy called Big Men for American network NBC, about a group of men attending a weight loss clinic