Timberlake: I can't imagine a day without singing

In the new animated comedy Trolls, the optimistic trolls are constantly singing and dancing, and they take time out every hour to hug each other.

The only exception is Branch, Justin Timberlake's character, who has lost his sense of joy and always prepares for the worst.

Timberlake, who says he's the opposite of Branch, describes the troll. "He isn't much of a people person.

"He doesn't sing, dance or hug, which makes him somewhat of an outcast - by his own choice - in the Troll community. I thought playing Branch's sarcasm and pessimism would be a lot of fun, he said."

He adds with a laugh: "I can't imagine a day without singing and music. I'd never really got to play the grump; there's a ton of irony there that Branch wants nothing to do with music."

When Branch is thrown together with Poppy (Anna Kendrick), the happiest troll in the world, to look for her friends who are captured by the villainous Bergens, they face numerous obstacles that leave even Poppy disheartened. So it is up to Branch to take up the cudgels to bring happiness back to the Trolls.

Opening here tomorrow, Trolls also features the voice talents of Christopher Mintz-Plasse, Russell Brand, Zooey Deschanel, Jeffrey Tambor, James Corden, John Cleese and Gwen Stefani.

It's been awhile since we've seen Timberlake, who is a nine-time Grammy winner, on the big screen. His The 20/20 Experience World Tour duties and fatherhood have kept him occupied over the last couple of years.

But now he's back - and not only as a voice actor. Timberlake also serves as executive music producer for the film and produced the soundtrack, which features four original songs in addition to a number of classic hits.

We are at The London West Hollywood at Beverly Hills to talk about Trolls. The 34-year-old, dressed in a Ferragamo jacket and casual shirt, with baggy jeans and sneakers, looks tired, which he attributes to his 18-month-old son, Silas Randall Timberlake, whom he shares with his wife of four years, US actress Jessica Biel.

What's it like being a new father?

Fatherhood is super scary.

Why?

Because you don't know what the hell you're doing. You figure things out as you go. It really lights you up in a way that you never imagined. Parenthood is great, it's amazing and it's hard. I feel like the real success of parenthood is getting to wake up the next day and fail all over again. (Laughs)

TROLLING ALONG: Justin Timberlake voices the character of Branch (above, left) opposite Anna Kendrick who voices Poppy. 

What makes you happy?

Being with my son. That's the thing that makes me happiest, and my family.

What makes you grumpy?

Whatever that moment is before I have my coffee in the morning... it's kind of like my grumpiest. And Los Angeles traffic..

How is writing for a movie different?

It is a different experience because you feel like, am I creating this music in a vacuum? But really, the funny thing is when you start to write it down and you start to put all (the) ideas together, in an interesting way, it opened me up.

You're making music that's not about you. Any time you're creating something that you haven't quite done before, it's easy to go okay, what are the rules to this scenario? But it makes you throw all the other ones out that you realise that you didn't realise you were putting on yourself.

What else would you like to achieve in your career?

I would like to achieve some sleep (laughs), but I also realise that may just be impossible. I think you're always transitioning into the next thing.

I feel really lucky to be on the career path that I've been on, but I definitely feel that I want to be as patient as possible. I feel like that's the best way to sort of respect it... just to be as patient as possible and try newer things.

Are you happiest singing, writing or acting?

If I had to pick one, there really is no way to describe the feeling of watching people sing a song that you wrote.

When was the last time you cried?

I'm a softie. But I think just watching your son learn the smallest thing can sort of take you to that place. I become a mess. (Laughs)

What was the most important lesson you have learnt, having started out in showbiz so 
young?

Probably a lesson learnt for the rest of my life is that you are really not in control of what's happening.

Tell us about your next album.

I've been in and out of the studio a little bit here and there, just kind of feeling my way through it.

Everything's still sort of in such an infant gestational stage. When it's done, it's done, and then I'll put it out but I don't like to rush it.

I feel like writing music for this movie opened me up to exploring different ways to write music and different styles and different genres, and just to explore.