AT LAST, A BABY FOR KELLY AT 50

KELLY Klein is finally about to become a mother. Childless through her 20-year marriage to fashion czar Calvin Klein, Kelly, at age 50, is having a baby.

Page Six has learned that Kelly is employing a surrogate mother in California to give birth to a baby boy using one of her eggs and the sperm of a friend. The due date is Nov. 1, when Kelly will fly out for the joyous event.

“She is expecting a baby and it is with a surrogate,” Kelly’s spokesman, Paul Wilmot, confirmed. He said she is keeping the identity of the father a secret for now.

One rumor is that Kelly’s brother-in-law was the donor, but Wilmot denied that, adding that no family member or relative was involved. Once her son is born, “Kelly will be living with the baby in New York and Palm Beach,” Wilmot added.

It’s no secret the brown-haired beauty has wanted a child for many years. But that became less and less likely as her marriage to the billionaire clothing magnate fell apart. The two lived separately for the last 10 years of their union before officially divorcing in April 2006.

Just before her 40th birthday, Kelly lamented how she could feel her biological clock ticking and said she might consider adopting at some point. “She has wanted a baby for a very long time. She loves children. She is very excited about this,” a friend said.

Another insider said that, “Even though Calvin has a daughter, Marci, from his first marriage, none of us ever really heard any talk of Calvin and Kelly starting their own family.”

The newborn will carry his mother’s maiden name, which is Rector. Less certain is the boy’s first name. A source told us Kelly was torn between Owen and Lewis, but Wilmot said that’s not the case.

Kelly, an avid equestrienne, isn’t the first well-known person to employ a surrogate. In 1995, gorgeous actress and model Toukie Smith and Robert De Niro became the proud parents of twin boys using a hired womb for her egg and his sperm.