Justin Timberlake and Jessica Biel are ''worried'' about confirming their baby news.

The couple - who are thought to be expecting their first child - are said to be holding back officially announcing the baby over fears of a mishap in the early stages of the 33-year-old actress' pregnancy.

A source told HollywoodLife.com: ''They've been trying for a while to get pregnant, there've been some issues so that's probably part of it too, they don't want to announce it until it's further along and they're out of the woods for a miscarriage.''

Justin, 33, also made it clear he is keen to keep the pregnancy private as he is ''freaked out'' by the thought of his children receiving ''unhealthy and scary'' attention.

The source explained: ''Justin is being super private right now, but that makes sense if Jessica is pregnant because he's always been bothered by the attention that celebrity kids get.

''It makes him angry and freaks him out because he thinks it's unhealthy for them and scary, so it's not a surprise at all that he's being so secretive about everything.''

The 'Mirrors' hitmaker and the brunette beauty - who have reportedly been trying for a baby since summer - are said to be delighted by the news.

A friend of the 'Total Recall' star said: ''Right now they are just enjoying the news for themselves.

''They just want a happy baby.''