Lithgow to appear in two 'HIMYM' episodes

How I Met Your Mother's executive producer Carter Bays has confirmed that John Lithgow will appear in at least two episodes of the show.

Lithgow originally signed up to play Barney's father in just one instalment, which is due to air on March 21.

However, Bays told TV Line: "[He] had such a fun time we booked him for another episode."

Bays also revealed that Lithgow's second appearance, expected to air in May, will be "a fun little story of him spending a night in Barney's world".

How I Met Your Mother airs on Mondays at 8/7c on CBS.