Britney Spears is spiralling out of control, often hitting nightclubs alone to party with strangers, according to the pop star's friends. One pal, who refused to be identified, appeared on US TV news show EXTRA last night (13FEB07) to reveal the extent of the single mum's wild nights out, explaining she was with the singer when she stripped to her underwear to try on a dancer's costume during a weekend trip to New York club One. The mystery friend, whose features were hidden from the TV camera, said, "She likes to drink champagne. Every time I see her she's got a champagne in her hand. "She was out almost every single night this week. I know she went to (nightclub) Tenjune alone four nights in the past week."