It's the magical answer to everything!
Actress Reese Witherspoon, who stars in the new animation 'Sing!' had to explain to her four-year-old son how she gets to voice a pig in the movie.
But the idea of his mum playing a pig when she's a human confuses him...
So she told him that it all happens by "magic". And then she realised - this is the answer to give all of her son's hardest questions!
Hear her explain how it happened in the video above.