Gwen Stefani pregnant

May 13, 2010, 9:31 GMT

Gwen Stefani is reportedly pregnant with her third child.

The No Doubt singer - who already has sons Kingston, three, and 19-month-old Zuma with husband Gavin Rossdale - is said to be expecting again but is experiencing bad morning sickness.

A source told America's OK! magazine: "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."

The 40-year-old star is keen to keep the pregnancy a secret for as long as possible so has been covering up her ever-expanding stomach.

At an event in New York last week, an onlooker said: "Gwen was pulling at her shirt to keep it away from her body. It seemed really strange - but then, when she turned to the side, I could see why. She definitely had a baby bump!"

Gwen recently revealed she is "running out of time" to have another child but is wary of expanding her brood.

She said: "No one could have prepared me for how awesome motherhood is, and how hard. I often feel like I'm running out of time. But I don't want to spread myself so thin that I can't be good for them. Poor Zuma, he'd be the middle guy.

"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."