Piers Morgan, JK Rowling in Twitter war over US travel ban

Piers Morgan and British author JK Rowling are in a Twitter war after Morgan clashed with Australian comic Jim Jefferies over US politics.

Undated file photos of Piers Morgan and JK Rowling became embroiled in a Twitter row Source: AAP

British TV personality Piers Morgan and British author JK Rowling are in a Twitter war over American politics.

He called her work "drivel" and she called him "amoral" after Morgan defended the US government's travel ban during an appearance on HBO's Real Time with Bill Maher on Friday.

Morgan faced off with Australian comic Jim Jefferies on the episode during a discussion of the executive order.

Morgan said it was "not a Muslim ban" and Jefferies directed an expletive at him.

Rowling tweeted that it was "satisfying" to hear Jefferies say that.

A flurry of tweets between Rowling and Morgan followed.