January Jones was 'excited' about pregnancy

For someone who doesn't want to reveal her son Xander's paternity, January Jones sure likes talking about the issue.

Maybe she doesn't have a choice -- the public interest in her kid's dad has been constant since the tot, almost 2, was born.

"It's just not something the public needs to know," she tells Net-a-Porter. "I don't divulge my sexual preferences. There are parts of your life – no matter what your job – that should remain private."

Jones plays Betty Draper on Mad Men. Like her character, she can be opaque and mysterious.

"When I was starting out, other actors advised me to keep certain things close to the vest. When you become a public figure people want to know everything about you, and then [they] pick it apart – it becomes negative. When my son asks those questions, I want him to [hear it from me]. I don't want him to be able to Google it."

As for pregnancy: " It was something I went in to knowingly, I was prepared mentally – and I was excited about it."

On her AMC series, meanwhile, Draper prepares to stand by her man when he runs for office.