There's a reoccurring trend amongst comedians that they don't just want to do comedy. The likes of Jim Carrey (Eternal Sunshine of the Spotless Mind), Steve Carell (Little Miss Sunshine) and Will Ferrell (Everything Must Go) have all dabbled with straight(ish) roles and have performed admirably. Ben Stiller can also be added to that list.

In 2010 he starred in the brilliant Greenberg. It's not a title that would jump out if you asked someone for five Stiller films, but it's without doubt one of his finest acting achievements in film. But as it wasn't Stiller doing his comic shtick, it didn't perform great at the box office.

It must be so frustrating for any actor trying to do something different, only to be ignored by a blinkered audience who only want you for one thing. Stiller clearly doesn't take it too personally, as he's back with yet another personal project with this adaptation of James Thurber's 1939 short story of the same name.

For sixteen years Walter Mitty (Stiller) has been working for the renowned Life magazine as a negative assets manager. But the digital age has finally caught up with it, and its new owners have decided that a printed version is no longer required.

Their timing couldn't be worse, particularly for Walter, who is smitten with a new colleague Cheryl (Kristen Wiig). For years he's been a day dreamer, but Cheryl's arrival has been the first real thing worth having in his life.

Although the printed version is to end, they want to go out on a high with the last issue, which is why highly respected photojournalist Sean O'Connell (Sean Penn) has shot something amazing for the cover. He has sent over the negatives to Walter, as he has done many times over the years. O'Connell informs Walter that negative 25 is the one to use, but on closer inspection, Walter finds that it is actually missing.

With his life on the precipice of great change, Walter decides to jump off into the great unknown and track down O'Connell wherever he is in the world and bring back negative 25 for the cover. It's a trip that's long overdue for Walter, and one brimming with unexpected real-life adventure.

Camping IS fun.Camping IS fun. Camping IS fun...

Although it shares the same name with Danny Kaye's 1947 film version, Stiller's is a completely different take on Thurber's story. His telling is less to do with multiple personalities, and more to do with the changes in life and how we react to them. The theme of analogue being replaced by digital acts as a nice allegory for Walter's life itself; he lives a standard analogue life, dreaming of a digital makeover. It takes a change completely out of his hands that acts as a catalyst to force him to re-evaluate his own destiny and finally do something about it.

It may also resemble a road trip in places, but ultimately the film itself is the journey of one individual who is finally spurred on to mentally and physically move on. Stiller gently emotes his character's chrysalis-tic transformation, delivering it with unusual subtlety. It's clearly what he was after as he also directed the film.

As a director, Stiller gives an obviously expensive Hollywood film a deliberate indie feel to proceedings. Everything from the quirky framing to the indie soundtrack belies its budget and everything it usually stands for.

And although his choice of a romantic lead in Kristen Wiig wouldn't be considered bold, the fact that he allows her to give a reserved and sweet performance – against type for the comedic actress – shows confidence.

The Secret Life of Walter Mitty, despite one or two of its flashy – and relevant – set pieces, is at heart, a wonderfully old-fashioned film, dimly reminiscent of classics of old. It's for that very reason that it probably won't have them queuing around the box offices, but that shouldn't deter you.

It's a film with a fascinating quietness about it, as well as a friendly and quirky sensibility.

Much like his Mitty character, Stiller is showing another brave and impressive side to his personality, that proves yet again that there's more to the actor than pulling puzzled faces and running around museums. It's also an indication that he's a talented director too with the ability to think outside of the box. Let's just hope that this side of his creative personality doesn't have to remain so darn secretive in the future.