The following excerpt is from an article at the chortle.co.uk website:

IT Crowd star Chris O’Dowd is set to star in a semi-improvised TV comedy made by Spinal Tap’s Christopher Guest.

Guest is working with Best In Show actor Jim Piddock on the genealogy comedy Family Tree, entertainment website Vulture reports.
Following the success of documentary shows such as Who Do You Think You Are? the series follows the efforts of one man tracking down his real family.

Otherwise details are thin on the ground, but the intention is said to be to make the half-hour, single-camera show both largely improvised and commercial-free, in the same spirit as Curb Your Enthusiasm.

Read the full article.