Jennifer Lopez is petrified she will 'forget how to act'.

The 39-year-old singer and actress – who has 15-month-old twins Max and Emme with husband Marc Anthony - is currently shooting her first movie for three years, 'The Back-Up Plan', and was worried she would struggle to readjust to working life.

She explained to US TV show 'Entertainment Tonight': 'The few days before, I got really nervous. I was like, 'What if I forgot how to act?’"

Jennifer plays pet shop owner Zoe in the film, an unlucky in love woman who is desperate for a child. She decides to conceive using artificial insemination, but meets love interest Stan – played by Alex O'Loughlin – soon after.

Despite her initial nerves, Jennifer soon fell back into the swing of movie making.

She said: 'I bring the babies to work with me. I love it. Honestly, one of the best days of my life was the first day back working on this film.

'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.'