Stalker shocker for BARBRA STREISAND, who’s suddenly ordered a total security lockdown at her Malibu compound, even insisting that her professional team – personal manager, business manager, publicist, and anyone else privy to her personal life – lock their office doors behind them without fail!

Reports an insider: “Barbra’s fallen victim to a very scary stalker, a fanatical Streisand lover who’s totally focused on her.

“Even though she’s had stalkers before, her security people are taking this guy very seriously – but they’re being tight-lipped about what’s convincing them that he’s the worst threat the star’s ever faced.

“Law enforcement has been alerted, and everyone close to Barbra’s been warned to take all precautions to keep details about her schedule, personal and business correspondence, phone messages, etc., totally secure.”