At the "Killers" press junket in London earlier this week to promote the European release of the movie, Katherine spoke to ITN about how she had found it more difficult than expected to mix motherhood and her career.

She explained, "I knew I was going to be a working mum. I knew I wasn't going to give up my career but you just cannot be prepared for that feeling when you're looking at them and holding your suitcase and they're reaching for you."

"So it is hard but I love what I do and I'm happy to be here and promoting this movie that I'm proud of and really excited about, so that kind of makes up for it... and I iChat," Heigl added, explaining that she had used the computer application to keep in touch with her daughter while she was away.

"I wish I could stay a bit longer and eat my way round London as I love food so much but I must go home to my lady," Katherine said.