Kelsey Grammer is banned from Piers Morgan's US chat show.

The former 'Frasier' star is no longer welcome on CNN's 'Piers Morgan Tonight' because he ''ran out of the building'' before an interview after seeing a photograph of his estranged ex-wife Camille Grammer in the studio.

Piers told US gossip website TMZ.com that the eccentric actor has now joined Madonna on his list of banned guests: ''There's a new one actually... Kelsey Grammer.''

He said he still has no idea why Kelsey bailed on their chat and revealed, ''it'll be the last time'' he will ever sit down with the actor.

Piers took to his twitter last week to vent his frustration after Kelsey unexpectedly cancelled his appearance on the popular chat show.

He wrote: ''Kelsey Grammer was supposed to be on my show now but ran out of the building. Strange. #CNN

''So, Kelsey Grammer saw a photo of his ex wife Camille in the open to our show and legged it. Extraordinary. Never had this happen before.

''I had a very friendly chat with Kelsey backstage, He said he was really looking forward to the interview. Weird. #CNN (sic).''

The 57-year-old actor was happy to discuss Camille in a subsequent interview with Anderson Cooper and told him that he wished he had been honest with his ex-wife about cheating on her.

The 'Boss' star met former flight attendant Kayte Walsh while he was still married to Camille - the mother of two of his children - and says he now regrets not immediately confessing to being unfaithful and trying to pretend everything was fine as they filmed her reality TV show 'Real Housewives of Beverly Hills'.