Guest Quentin Letts clashed with the presenter over the UK's treatment of refugees, saying: "There's no point talking to you."
The divisive presenter has taken aim at his former employer as he gears up to launch his new TV venture.
After 15 years, the GB News anchor stepped down as a host on This Morning in December.
Tabloid reports recently suggested the stars were a little more "pampered" than we see on screen.
Piers' comments about Meghan Markle' led to a record number of Ofcom complaints earlier this year.