Rebecca Romijn is dreading her 40th birthday.

The X-Men actress will hit the landmark age on November 6. The star is not looking forward to celebrating.

"It's funny: All year long I kept saying, 'I think I want to do a really big party,' and the closer you get to it, I don't really feel like celebrating," she told Us Weekly.

The former model, who is married to 38-year-old actor Jerry O'Connell, is just too "sad" to be leaving her thirties.

And she can't imagine what the next decade might bring.

"I loved my thirties! It's not like I'm not looking forward to 40; I'm just sad to be leaving my thirties," she explained.

Rebecca doesn't have much time to fret over hitting the big 4-0, however.

Being a mom to three-year-old twin girls, Charlie and Dolly, keeps her more than busy.

"They fought over their first article of clothing this week, which is crazy because they have such different styles," she laughed, musing their tug-of-war over a pair of tie-dye leggings was "a knock-down drag-out fight".