Newlyweds Fergie and Josh Duhamel's families are unfazed by new rumours the pop star is pregnant, because celebrity bloggers are always speculating over whether she is with child.

The couple tied the knot at a low-key vineyard ceremony in Malibu, California on Saturday.

They jetted out of Los Angeles International Airport on Sunday to begin their honeymoon, but not before Fergie joked to photographers, "I'm pregnant with twins."

Her cheeky comment has sparked fresh reports the stars are expecting - but Fergie's mum Terri Jackson insists rumours they are starting a family are premature.

Asked whether she's to become a grandmother, Jackson laughed, "Yeah, that's it!"

And the proud mother is well aware the blogs have been rampant with the false baby news for months, adding, "Josh's mother (is like), 'Would she hurry up and have that elephant?!'"