Zoe Saldana's Crossroads co-star Britney Spears has accidentally let it slip that the mum-to-be is expecting twins.

Speculation surfaced this summer (14) that the Avatar beauty and her husband, Italian artist Marco Perego, are preparing for a double bundle of joy, but Saldana has been tight-lipped about her pregnancy, only confirming that she is indeed with child.

But following an impromptu reunion with her one-time co-star at Los Angeles' Lax airport on Monday (08Sep14), Spears revealed the actress has a double delight on the way.

As the singer arrived in New York City to debut her lingerie line at New York Fashion Week, she was asked by Entertainment Tonight if she would ever do another film with Saldana, and her answer revealed the actress' exciting news.

The pop star said, "Who knows? That’s a very good idea. But she's pregnant with twins right now. So I'm sure she's got a huge future ahead of her."

With two young sons only one year apart, the Toxic hitmaker offered some advice to Saldana, revealing she told her, "You're not ready. You don't know what you're in for."