Britney Spears felt ''alienated from the public'' when she went through a tough time in her life.

The 32-year-old pop star - who exhibited erratic behaviour, including shaving her head, between 2007 and 2008 and was placed under a conservatorship - has recalled feeling so harangued by paparazzi photographers, who would follow her every move, she didn't want to leave her house for nearly two years.

In a candid new documentary 'I Am Britney Jean', which aired on US TV last night (22.12.13), Britney said she felt ''alienated'' from her fans during the ''trying time''.

She added: ''But as time passed, they lightened up and they went away after I wouldn't come out of the house for two years.

''It was a trying time. It was kind of confusing for me. Personally, I'm a shy person and I'm particularly not really made for this industry because I am so shy. It's not something I deal with so well.''

The 'Work Bitch' singer, who is due to begin a two-year residency titled 'Britney: Piece of Me' at Planet Hollywood in Las Vegas on Friday (27.12.13), also spoke of her struggles dealing with pressure, admitting she tends to keep her issues to herself.

Britney explained: ''Pressure is a funny thing. Sometimes I tend to go inward when I'm under pressure. I tend to keep it all in. I don't express myself too much. If I'm really nervous I'm really quiet. But I think I thrive under pressure.''