From Tom Hanks to Iggy Pop, Letters Live proves the letter shouldn't become extinct

As musician Kelvin Jones takes to the stage, he asks the audience at the huge Freemasons' Hall to do something "very un-English"; take out their phones, shine their flashlights and sing along. Apart from highlight how many people definitely don't bother turning off their phones during performances, it transforms the 1,700-seater hall into a intimate setting for Letters Live – the charity event which sees an all-star line-up read letters from history.

The subjects of the letters only reinforce that feeling. Sherlock's Louise Brealey read a piece from the Letters In The Mail project, which send subscribers a handwritten letter from a different writer every two weeks, in an attempt to offset the vast amount of junk mail we all get. One she read is from a woman visiting her lover, who is a writer and insists the reason they're having sex so much is for "research". Toby Jones read a number of letters from Napoleon to his wife Joséphine in which he wails over the fact she has not written to him in two days, while he is off conquering Europe.

Towards the end of the evening, a letter to JK Rowling provides the most touching moment. From the mother of a young cancer patient thanking the Harry Potter author for "building a castle for her to move into when [her] prognosis got worse.

"Mrs Rowling, cancer threatened to take everything from my daughter, and your books turned out to be the fortress we so desperately needed to hide in."

These letters could serve as a gentle nudge to everyone who wants to be a writer

But it's not just a night for a sob and a soul-search. Stephen Mangan performed a brilliant letter from an aspiring Harvard student rejecting the rejections he had received from universities: "Having reviewed the many rejection letters I have received in the last few weeks, it is with great regret that I must inform you I am unable to accept your rejection at this time."

Stranger Things' Charlie Heaton read a piece by one Thomas J Hanks to a director about how he was to "discover him". Iggy Pop's response to a piece of fan mail that was so good he "read the whole fucking 20 pages" was read by the smooth-as-ever Jarvis Cocker.

No one received a penny for writing these letters, yet they told stories as rich and personal as any you can see on stage or screen. Tonight could serve as a gentle nudge to everyone who wants to be a writer but "can't find the time" to finish the novel they started six years ago, or "doesn't know what to write about". When you're writing to someone, you will find something to say, and that is a story in itself. For someone trying to find their writing voice, it's time to put down the phone and pick up your pen.

In a time where we can communicate solely using emojis, what's the appeal of writing a letter? Receiving one has become a sort of occasion – a nice surprise rather than the cause of Napoleon's grief. The chances are, your string of texts won't go down in history. These letters already have.

Letters Live runs at Freemasons' Hall, Holborn until 8 October. For more information, click here.