Rebecca Romijn is "shocked" at how different her twin daughters are.

The 37-year-old actress - who had twins Dolly Rebecca Rose and Charlie Tamara Tulip with husband Jerry O'Connell 16 months ago - loves every aspect of motherhood and takes delight in watching how her non-identical girls' personalities are changing.

She said: "It's just shocking, seeing how different they are and watching their personalities develop. It's better than I could ever have expected."

'Obsessed' actor Jerry also claims Rebecca is a hard working mother who rarely has time off.

He said: "She's the first one up, last one to bed."

To celebrate Mother's Day in the US yesterday (09.05.10), Jerry spoiled his wife with presents and helped the toddlers create their own cards in keeping with a family tradition.

He explained to People magazine: "We have a rule in our family where you have to make cards - you can't buy them, you have to make them - so I made a couple of cards. I got the girls to hold the crayons and scribble."

It is not only in their personalities that Charlie and Dolly are different.

Rebecca has previously spoken about their radically different appearances.

She said: "Dolly looks exactly how I looked as a baby and Charlie looks exactly how Jerry looked as a baby. "