Evan Rachel Wood has ''separation anxiety'' when she's parted from her son.

The '13' actress finds it impossible to be apart from her four-month-old tot - whose name she has yet to reveal - for any length of time.

She told UsMagazine.com: ''I've been having separation anxiety because I'm so used to him being right here all the time. They kind of become a part of you, you know?

''It was my dream to be a mom, so I'm loving it. I love it.''

The 26-year-old star - who is married to 'Billy Elliot' actor Jamie Bell - remained coy when quizzed about what her son is called, but did admit the couple had named him before he was even born.

Evan joked: ''We asked him while he was in the womb if that's what he wanted his name to be - to kick - and he did, so there you go!''

The doting mother is delighted with her child's progress and can't believe how much he's changed over the last few months.

She cooed: ''He's smiling and laughing. He started rolling over. He's grabbing things. You know, he's making oohs and aahs.''

The actress is taking a well-deserved break from acting and was thrilled her new movie 'Charlie Countryman', which also features Shia LaBeouf, wrapped just before she found out she was expecting.

Evan added: ''I was lucky because I had done three films and got pregnant so I was like, 'I've got stuff in the can. I'm taking a break!'''