Hiddleston made his debut as the comic book baddie in Kenneth Branagh's 2011 release Thor, alongside Chris Hemsworth as the titular Norse god, but his character also played a prominent part in the first The Avengers outing in 2012, and he was ecstatic when Whedon asked him to reprise the role of Loki for the collective superhero movie.
In a lengthy message he sent to Whedon, he refers to children's classic Charlie and the Chocolate Factory, writing, "I am so excited I can hardly speak. The first time I read it (The Avengers screenplay) I grabbed at it like Charlie Bucket snatching for a golden ticket somewhere behind the chocolate in the wrapper of a Wonka Bar."
Of his role, he continued, "It's grand and epic and majestic and poetic and lyrical and wicked and rich and bada** and might possibly be the most gloriously fun part I've ever stared down the barrel of playing. It is just so juicy...
"I might be biased, but I do feel as though you have written me the coolest part."
The flattered filmmaker responded to Hiddleston and joked, "Tom, this is one of those emails you keep forever. Thanks so much. It's more articulate (and possibly longer) than the script.
"I couldn't be more pleased at your reaction... Thank you again."
The email exchange is featured in a new book about the director, titled Joss Whedon: The Biography.