Los Angeles - 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 earlier this week, 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 began a two-year residency titled Britney: Piece of Me at Planet Hollywood in Las Vegas on Friday, 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."