Trump in a tweet, hailed himself as "best selling" author.
"After having written many best selling books, and somewhat priding myself on my ability to write, it should be noted that the Fake News constantly likes to pour over my tweets looking for a mistake. I capitalize certain words only for emphasis, not b/c they should be capitalized! (sic)" Trump had tweeted.
Rowling, the author of the wildly popular Harry Potter series, pointed out that Trump should have written "pore over" rather than "pour over".
After posting multiple tweets reading 'hahaha' in repetition, Rowling called out Trump's error, and gave him an appropriately misspelt title.
"Seriously, @realDonaldTrump is the Gratest Writer on earth," the author tweeted.
'Pore over' and 'pour over' are homophones, meaning that they sound the same but have different meanings.
Trump soon deleted his original tweet and posted a corrected version.
Dictionary Merriam-Webster's Twitter account also pointed out the error in a tweet calling out Trump's grammar. Hollywood writer James Gunn and TV host Jimmy Kimmel also called out the president.
Rowling has often criticised Trump on Twitter in the past, once writing "Voldemort was nowhere near as bad" when a publication compared Trump to the Dark Lord.
Voldemort, also known as He Who Must Not Be Named, is the main villain in the Potter series.
Trump has frequently misspelt words and even inspired a worldwide meme when a tweet mentioned 'covfefe', a word whose meaning is unknown.
Merriam Webster dictionary too responded to Trump’s grammatical errors and helped as much as it could.