Chinese counterparts: Tong Dawei (left) voices the alien Oh, and singer and actress Li Yuchun voices the teenager Tip in the Chinese-dubbed version of Home.[Photo provided to China Daily]

"I bought the book to read to my boys, who were 5 and 7 years old at that time. At first, I wasn't thinking about it. But in a couple of hours, I started to realize it could be a pretty good animated movie," recalls Johnson, who says that years of working with DreamWorks has pushed him to always look for ideas.

The veteran animated filmmaker, famous for Antz (1998) and Over the Hedge (2006), was so excited by his discovery he sent an e-mail to Katzenberg at 2 am, telling him he had found an "amazing book".

"It was a weekend. And by Monday, we already had the (adaptation) rights of the book," he says, laughing.

However, the director says he faced many "obstacles" when attempting to turn the book into a movie, including casting the voice actors, writing the script and transforming the visual images.

When Jim Parsons, popular in China for playing the character Sheldon in the hit series The Big Bang Theory, and Barbadian singer Rihanna agreed to dub Home, the director described it as "getting the green lights".

"I was so surprised to hear that Jimmy is so popular in China. He is quite different from both Oh and Sheldon, who doesn't understand people and pushes them away. Oh crazily loves friends and really wants to have a family," says Johnson.

"But Jimmy is quite relaxed and personable, and he even moves quite differently (from Sheldon)."

When asked to judge the Chinese voice actors' performance, Johnson says he searched for their previous work and was excited to find both of them have "musical and exceptional voices".

Johnson says Home is dubbed in 40 languages and has 52 versions, as some countries share the same language but cast different voice actors.

Li shot to fame in the Chinese reality show Super Girl, but has been criticized by Chinese media for her "aggressive" voice, far removed from Rihanna's "soft" style. Johnson, however, gives her his warm support.

"When an animated movie travels to another country such as China, it doesn't need someone to imitate the English version, but someone to make the characters in their interpretation... It can be their job to tell the story in their unique way," he says.

"The movie is about making a judgment about somebody and then finding the judgment was done too quickly," says the director.

In the movie the aliens "Boov" find their biggest enemy "the Gorg" are not actually evil. Perhaps Chinese audiences will find the local actors are not so bad after all.