Madonna Feud With Piers Morgan One Sided?

You'll recall ... Piers publicly banned Madonna from his CNN show on Twitter Tuesday, writing, "Welcome to Twitter. You're still banned from my show. Love Piers X."

Madonna's manager Guy Oseary thumbed his nose in response, tweeting back Madonna had already been invited to Piers' UK show -- so Piers extended the ban worldwide.

Piers refused to elaborate on what's really behind the feud -- on his way out of an L.A. supermarket today -- telling us, "It's a private spat."

Piers added, "Madonna can come on [my] show, but she has to get on bended knee and apologize to me ... on TMZ."