Is Kristen Stewart pregnant?

They might have been keeping people guessing on the status of their relationship but actress Kristen Stewart has revealed she has already started talking about kids with her "Twilight" co-star Robert Pattinson.

The secret came out as the pair desperately tried to dodge a question about their romance on the Oprah Winfrey Show, reports thesun.

When the US host asked them whether rumours about their relationship were true, Pattinson joked: "Kristen’s pregnant." Looking uncomfortable, Stewart continued: "He really likes to shock people because he thinks it’s funny. We’ve actually had this conversation."

Quickly correcting her slip-up and pointing to her stomach, the 20-year-old actress added: "He’s having the baby because I can’t."