Did you notice this tribute to Rupert Grint in the Half-Blood Prince?

It was VERY subtle.

Is there anything the internet loves more than a good old Harry Potter theory? And over the years we've been treated to many. From the real meaning behind Snape's first words to Harry, to how the Prisoner of Azkaban predicted Dumbledore's death, the theories really are endless.

As if we needed more proof that author J.K. Rowling is an actual genius, we've also been privy to an array of hidden Harry Potter book details lately. Now we're back with another, and it shows that Rowling really did think of quite literally everything.

As recently pointed out by one very eagle-eyed fan, it appears J.K Rowling included a very subtle shout out to none other than Rupert Grint in the 2005 novel, Harry Potter and the Half Blood Prince.

If you're now planning on re-reading the penultimate novel in the Harry Potter series to find said shout out, then stop reading this now. For those of you who simply can't wait, carry on.

Fans of the books and film franchise will remember that in Harry's sixth (and final) year at Hogwarts his new positions master, one Horace Slughorn, showed a very unsubtle favouritism towards Harry.

As well as favouring Harry, Slughorn also took to the likes of Hermione Granger (the brightest witch in her year) and Ginny Weasley (who performed a rather impressive hex in front of Slughorn on the Hogwarts Express) amongst other students he considered exceptionally gifted.

Unfortunately poor old Ron didn't quite fit this bill in the potions masters eyes, with Slughorn failing to even remember his name, as the below paragraph taken from Harry Potter and the Half Blood Prince proves:

'I have had it all tested for poison,' he assured Harry pouring most of the first bottle into one of Hagrid's bucket-sized mugs and handing it to Hagrid. 'Had a house-elf taste every bottle after what happened to your poor friend Rupert,'

Did you spot that? The sneaky little shout out to Rupert there? Clever J K Rowling, very clever.