The debutante author took to Twitter to share the letter, thanking the veteran actor for his words of encouragement.
"So honoured to get this in the mail! Thank you so much @SrBachchan for taking the time to write this to me - it is such an encouragement!! #theperilsofbeingmoderatelyfamous #thursdaythrills," Soha captioned the picture.
In the letter, dated January 9, Bachchan lauded the actor for her writing skills and sense of humour.
"Even though on the surface you are sort of reticent and shying away from the spotlight, your genuine and funny sense of humour has been skilfully portrayed confirming that you possess a steely something in the middle that says 'You know what, I'm actually really really good at this, and this is what I can do, and now I have done it'," he wrote.
Published by Penguin India, the book hit the bookshelves in December last year.
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