Victoria Beckham likes to ''take the mickey'' out of herself.

The singer-turned-designer is famed for her poker face and rarely flashing a smile for the cameras, but she insists she secretly has a great sense of humour and doesn't take herself too seriously.

She told ELLE Singapore magazine: ''People are probably surprised that I have a sense of humour. I like to take the mickey out of myself. As much as I take what I do very seriously, I also want to have fun.

''I like to poke fun at myself... And I think that surprises people.''

The 40-year-old star - who has sons Brooklyn, 15, Romeo, 12, Cruz, nine, and two-year-old daughter Harper with her husband David Beckham - puts a huge amount of pressure on herself to make her fashion empire a success and says her biggest business motivation is surpassing her own expectations.

She added: ''I'm not afraid. I think you can learn from everything. I don't ever think of the negatives, I think of the positives. I'm not competing with anybody else out there; I'm just competing with myself.

''I never went into this to prove anything to anybody, other than myself. I think if you're too afraid of failure then you won't challenge yourself, then you won't move forward. I like to challenge myself.''