London: British comedian Russell Brand has acknowledged sleeping with a 16-year-old girl when he was at the height of his fame, but said while it was "exploitative" it was not illegal.

"The age of consent is 16 and I did sleep with a 16-year-old when I was 30," Brand told US right-wing host Megyn Kelly in a YouTube show broadcast Wednesday.

"But when I was 30, I was a very different person. I was a lot younger and I was an immature 30-year-old."

He insisted it had been a consensual encounter, but added "when you're a famous man that has the ability to attract women... I think involves exploitation".

"I think it is exploitative," Brand admitted to Kelly on her show, adding: "I recognise that my sexual conduct in the past was selfish and I did not apply enough consideration... to how that sex was affecting other people."

The 50-year-old, who was once married to US pop star Katy Perry, has pleaded not guilty to sexual offence charges in the UK involving a total of six women, including rape and sexual assault.

His trial is due to start in October in a London court.

Brand, once a left-leaning political campaigner, has rebranded himself as a conservative and Christian guru to millions of social media followers.

Born in 1975 to working-class parents in Essex, east of London, Brand began his stand-up career as a teenager, eventually working as an MTV presenter and host of a reality TV series.

He presented a show on the BBC's Radio 2 station between 2006 and 2008, but quit after an on-air prank when he left an explicit voicemail for "Fawlty Towers" actor Andrew Sachs. (AFP)