The British TV host objected to fellow show guest and Australian comedian Jim Jefferies' reference to President Trump's "Muslim travel ban", insisting the ban was not aimed at Muslims. Jefferies quickly told Morgan to "f**k off", resulting in huge applause from the Los Angeles studio audience.

Harry Potter author Rowling was watching the show and the often-named 'Queen of Twitter' couldn't wait to have her say. "Yes, watching Piers Morgan being told to f**k off on live TV is *exactly* as satisfying as I'd always imagined," she tweeted, prompting over 51,000 of her Twitter followers to retweet the message and more than 150,000 to 'like' it.

Morgan, who is friendly with President Trump, struck back with his own tweet: "This is why I've never read a single word of Harry Potter". This prompted Rowling to respond: "Because you had a premonition that one day the author would roar with laughter at seeing you called out for your bulls**t on live TV?"

She also made another comment about Harry Potter: "If only you'd read Harry Potter, you'd know the downside of sucking up to the biggest bully in school is getting burned alive."

Morgan had little to respond with and resorted to disputing another of J.k. Rowling's unofficial titles - 'British national treasure' - by referring to her as someone "who wrote a few wizard books".

This prompted J.K. to fire off the latest missive in the exchange for now - an image of herself winning British Book of the Year in 2006 for Harry Potter and the Half Blood Prince. One of the books also in contention for the title was an autobiography by Piers Morgan. She captioned the image: "#StillHurts".

The Independent, meanwhile, spoke for most observers of the bitter war of words in tweeting: "Jk Rowling is systematically humiliating Piers Morgan in front of millions."