Courteney Cox's daughter, Coco, is ''nervous'' about becoming a sister.

The 'Friends' actress' ex-husband, David Arquette, is set to have a baby with his girlfriend Christina McLarty later this year, and while Courtney and their nine-year-old daughter were initially shocked, they're now excited by the news.

Speaking to talk show host Ellen DeGeneres, Courteney said: ''At first she was nervous because it's a big deal. At first, I was nervous! I was like, 'Woo, heavy.' Now it's great.''

Although Courteney and David split in 2010, they have remained committed to raising their daughter together, and still get along well.

She added: ''We actually all had dinner the other night. The whole family. It's a very unique relationship. All of us, like literally, me and Christina and David and Coco - it's great.''

Coco may be looking forward her father's new arrival, but she doesn't want her mother to follow suit and make any dramatic changes to her life.

Courteney added: ''It's almost like she's a little bit of a tick - she is on me! She doesn't want [any] changes in my life.''