OK! Exclusive: Rebecca Romijin Had Fertility Treatment

Today Rebecca Romijin and Jerry O'Connell announced that they're expect twins.

But OK! can exclusively reveal that the happy news has been a long time coming for the parents-to-be.

They're reps say that the baby girls, due this winter, were conceived with any fertilization treatments.

But we've learned that the X Men star had three rounds of in vitro fertilization treatment before she finally got pregnant.

The couple, who celebrated their first wedding anniversary on July 14, have even been going to an acupuncturist in hopes of making the in vitro stick.

Insiders at an acupuncture clinic in Thousand Oaks, Ca., say that Rebecca's been getting treatment twice a week for more than a year, and Jerry goes as well, getting therapy to make his swimmers more powerful.

"They were trying to conceive in any way possible," says our source. "She and Jerry would come in to the clinic together, always dressed low key, and acting very down to earth and sweet.

"Once, around the holidays, Rebecca gave the staff a large gourmet muffin basket, which kept her in good stead, since she often canceled appointments at the last second."