No Doubt beauty Gwen Stefani is reportedly pregnant with her third child, according to a US magazine.

The blonde bombshell and husband Gavin Rossdale are already parents to sons Kingston, three, and 19-month-old Zuma.

"Gwen is having a really rough time this pregnancy. She had all-day morning sickness for a while with Zuma, but she's sicker this time round and has been feeling exhausted and dizzy," a source says.

Recently, Gwen said another child would be a "miracle".

"I'm not focusing on it right now, but it's not up to me anyway, you know? These things are miracles, so we'll see," she said.