Justin Timberlake feared fans would hate grumpy Trolls character

Justin Timberlake was concerned his "cantankerous" character in new animated movie Trolls would turn film fans off.

The pop superstar-turned-actor voices town outcast Leaf in the family comedy, opposite the always-optimistic Poppy, played by Anna Kendrick, and the two trolls are forced to team up to rescue Poppy's friends after they are kidnapped by giant monsters.

Justin and Anna joined Trolls directors Mike Mitchell and Walt Dohrn, and producer Gina Shay at Comic-Con in San Diego, California on Thursday (21Jul16), when they shared a preview of the picture with attendees.

During a panel discussion after the sneak peek, Anna revealed she loved channelling her character's feel-good nature, and actually felt she may have taken it a little too far.

"I couldn't help but be a little psychotic, and they (filmmakers) really embraced that, I think especially in that song Get Back Up Again," she told the crowd. "You're like, she is unhinged! An unbalanced little troll.

"We wanted to make her really happy but not the kind of thing you couldn't stand for a 90-minute movie. She's got layers. She's messed up. It's the kind of tiny troll that I like."

Timberlake, on the other hand, admitted he was initially worried Leaf was too grumpy for his own good, reports Entertainment Weekly.

"I remember working with Mike and Walt and being extremely concerned that he was just going to be too cantankerous, that no one's going to like this guy," he confessed.

However, the completely different personalities of their characters worked well and the chemistry was obvious onscreen.

Justin said, "It just became more funny that they were so polar opposites of each other."

Despite little Leaf's downcast nature, Justin, who also oversaw the music for the project, claims working on Trolls and its accompanying tune Can't Stop The Feeling gave his daily mood a big boost too.

He explained, "I've never written a song like that under these type of circumstances, but when I started to write the song, I was like, 'This actually makes me feel really good.'

"It's nice to be a part of something that you can put out in the world and it just makes people happy and there's no rhyme or reason to it and you can be unabashed about it. That's my favourite thing about this whole thing."

And Justin wasn't the only one who enjoyed recording his lines and lyrics for the film.

Anna added, "Every time I got an email that said these guys wanted to do another session, it made my weak. I would just be looking forward to it all week, getting to go in and say these weird lines about cupcakes and rainbows... This is the first time I've ever rushed to watch footage."

Trolls, based on the popular toy dolls, is set for release in November (16).