It turns out this capability is also accessible on Android phones too. Needless to say HP fans are thrilled.

Harry Potter 20th Anniversary: Return to Hogwarts' on HBO provided a pleasant start to the new year for Harry Potter enthusiasts. They now have another reason to rejoice after learning that they can 'cast spells' using their cellphones.

It turns out that saying 'Lumos' to Siri, Apple's virtual assistant, turns on a phone's flashlight, and this capability is also accessible on Android phones. The flashlight is turned off by saying 'nox,' making users feel like real-life wizards.

Fans of the magical youngster flocked to Twitter to announce the news with gifs and memes of Harry Potter. Here are a few examples: “Just discovered that if you say “Lumos” to Siri, the flashlight turns on. Well played, Apple, well played." “Say “Lumos” to Siri/Google assistant." “Harry Potter fans.. tell your phone “hey Siri, Lumos” you won’t be disappointed". “I just said “Hey Siri, Lumos” and my light turned on… the said “Hey Siri, Nox” and it turned off. My mind is blown. #HarryPotter"

Here are Potterheads reaction on Twitter -