Actress Olivia Wilde has her own favourite singer which is pop star Justin Bieber who she proceeded to call the 'greatest singer on Earth'.

The actress and director, 39, appeared on an episode of 'SubwayTakes', a one-minute talk show set on the New York City subway, and revealed her very own hot take: 'people who are good at singing shouldn't be allowed to do karaoke', 'People' reported.