The 29-year-old star claims he is still not fully comfortable either as a singer or a performer, despite winning several awards for his work.
“I think I’m equally insecure about both of them. I’ve been doing this for two thirds of my life and I still consider myself pretty young but I think that’s the part you battle with all the time.
“When you’re creating your art, that’s the best part. Your senses are on a creative high and then the part where everyone gets to see it and comment on it, that’s the part I think you battle with until you die.
“It’s absolutely terrifying,” he said.
Timberlake doesn’t want to be known only for either his acting or singing talents and thinks his early work on the children’s TV show gave him a solid grounding in both professions.
Timberlake, who voices the character Boo-Boo Bear in upcoming animated movie Yogi Bear, added: “It’s no secret I was trained as a very young kid on a TV show with a lot of other extremely talented actors and singers – Christina Aguilera, Ryan Gosling.
“I think we were all trained in the arts, be it song, dance or acting.”