The eight half-hour episodes will see experts submit their theories about life and the universe for examination by a panel of two comedians and a guest celebrity.
After a thorough interrogation, the panel will make a final decision on whether the theory is worth keeping.
The show will be hosted by Outnumbered writer Andy Hamilton, who is joined each week by stand-up Reginald D. Hunter.
Executive editor of BBC comedy entertainment Katie Taylor said of the show: "It's Only A Theory explores refreshingly new territory for comedy entertainment as Andy and Reg lead us on a comic journey in their quest for knowledge."
