Jennifer Lopez emotional admission of secret fear.

The superstar was wracked with terror  before returning to work to lens new flick The Back-Up Plan because she was scared she had forgotten how to "act"!

After putting her career on hold to care for twins Max and Emme born last year, she stayed home to nurse her spawn but now La Lopez is back filming but not before confessing her long layoff jitters

"The few days before I got really nervous I was like, what if I forgot how to act?" J.Lo divulged.

But she conquered her anxiety by bringing the twins to set with her.

"I wanted to do this film really badly and bringing my babies with me that first morning, I was like, 'Oh my God, they're with me, I'm making a movie, they're here!'

"It's great having kids on set. It's the best."