Jessica Biel is worried Justin Timberlake ''isn't ready'' to become a dad.

The 'Total Recall' actress - who is rumoured to be pregnant with her first child - has reportedly aired her concerns about the 33-year-old singer's commitment to fatherhood, with a source revealing that he ''isn't ready to give up touring''.

The insider added to The National Enquirer magazine: ''They've spent little time together during Jessica's pregnancy. Justin pretends he doesn't have a care, but you can see how antsy he is.

''He knows it won't be long before his life changes ... now she's concerned it might be more than Justin can handle.''

Meanwhile, Justin's former 'NSYNC bandmate, Joey Fatone has appeared to confirm the pregnancy, explaining that the 'Mirrors' hitmaker told him the good news ''a while ago'' but he now has permission to ''talk about it''.

He said recently: ''He told me a while ago, and I kept my mouth shut. But now I can talk about it!

''Jessica is awesome, and Justin is a kid at heart. [They'll have] fun.''

The couple have yet to confirm the news officially, with a source previously claiming that they were ''worried'' about announcing it.

The insider explained: ''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.''