Variety reports that "Family Tree" will be a UK/US co-production that will air simultaneously on BBC 2, and that will star "Bridesmaids" own Chris O'Dowd as well as Guest (who'll direct) and his frequent collaborator and series co-creator Jim Piddock.
O'Dowd will play a drifting 30-year-old who decides to explores his family roots after receiving a mysterious collection of belongings from a great-aunt he's never met.
When first reported on back in May, the proposed show was compared to Larry David’s "Curb Your Enthusiasm" in terms of its use of improvisation -- no surprise, given that's been Guest's preferred style in his filmmaking. According to Variety, no premiere date has yet been set.
Guest hasn't directed a film since 2006's awards-season satire "For Your Consideration," though he did oversee that focus group sketch at the Oscars earlier this year. O'Dowd recently appeared on another HBO series -- he played Thomas-John, the insecure venture capitalist who angled for a threesome with Jessa (Jemima Kirke) and Marnie (Allison Williams) in "Girls" and who made a surprise appearance in the season finale.