Charlize Theron ''was making out with [herself] at seven''.

The Oscar-winning actress - who has recently been romantically linked to fellow Hollywood star Brad Pitt - revealed she mastered her kissing technique by smooching the inside of her elbow as a child.

She confessed: ''I was making out with myself at seven, I made out with dolls and with myself in the mirror.''

The 43-year-old star - who has denied the rumours linking her to Brad, 55 - also joked that her childhood antics explain why she's currently single.

Charlize - who has two adopted children, Jackson and August - told 'The Ellen DeGeneres Show': ''It's why I'm single.''

Despite being one of the most in-demand actresses in Hollywood, Charlize previously admitted she's convinced she'll get ''fired'' from every movie she works on.

The blonde beauty confessed to having some deep-rooted insecurities about her acting talents.

She said: ''I still have this every single time I start a job, 'I'm gonna get fired. They're gonna find out I'm a terrible actor. This is gonna be the one. This is gonna be the job where they all find out I'm just a total lie.'''

However, Charlize thinks it's important that female performers know their true value.

The 'Tully' star reflected: ''We just need to not be so polite about it and say what we want? ... The amount of traction and the amount of women who are being empowered by other women to step forward and actually speak their truth - I know in my life I've never seen anything like that.

''This is a rock rolling down a mountain really fast, and I'm quite enjoying watching it.''