Also appearing alongside host Kelly Ripa during the first week of the New Year will be Standing On Ceremony's Mark Consuelos (Jan. 2), David Duchovny (Jan. 4) and Rob Lowe (Jan. 5-6).
Celebrities have stepped in to take over for former co-host Regis Philbin, who departed the show Nov. 18.
Parsons, who made his Broadway debut in Normal Heart, is best known for his work on "The Big Bang Theory." As previously announced, he will star in Roundabout Theatre Company's revival of the Pulitzer Prize-winning comedy Harvey, beginning May 18, 2012, at Studio 54.
Duchovny starred Off-Broadway in The Break of Noon, and Lowe has been seen on Broadway in A Little Hotel on the Side.
For more information, visit www.livewithkelly.tv.