The currently untitled series from Greg Malins and Greg Berlanti will star Walton as Nick, who realises after a health scare that he is in love with his best friend Wendy (JoAnna Garcia).
David Walton is currently listed as a guest star in the project as it is in second position to NBC's current sitcom Bent, in which he currently stars opposite Amanda Peet.
However, Bent is unlikely to return for a second season after its initial run of six episodes, meaning he would be able to be upped to a main star, according to Deadline.
Bryan Greenberg had originally signed up for the main role of Nick, but reportedly exited production after yesterday's (April 4) script reading.
The project has been known as Oh F**k It's You but doesn't currently have an official title.
Heroes actor Greg Grunberg recently signed up to star as Wendy's brother Charlie in the multi-camera comedy.
The project is being developed by Friends, How I Met Your Mother and Will & Grace producer Malins alongside Dawson's Creek, Everwood, Eli Stone and Brothers & Sisters alum Berlanti.
David Walton announced the pregnancy of his wife Majandra Delfino earlier this year.