Jessica Biel and Justin Timberlake are still hunting for a perfect wedding location.

The Hollywood couple are set to tie the knot in August but they have yet to find a venue that they like and will be big enough to hold all their guests.

A source told Us Weekly magazine: ''It needs to be in California and offer plenty of room! It will be a big wedding. They have lots of people they want to invite.''

However, Jessica is getting plenty of help from Justin's mother, Lynn Harless,who is giving her future daughter-in-law lots of advice on planning the big day.

The source said: ''She's helping Jessica with every little thing.''

But one thing Jessica - who split from Justin last year only for them to rekindle their romance before Justin popped the question - has decided on is the designer of her dress.

The source revealed: ''Monique Lhuillier has sent over some sketches. She's Jessica's first choice.''

Despite refusing to confirm their engagement in public, Jessica showed off her engagement ring at a party in New York earlier this month, with witnesses guessing it could be vintage.

A source said: ''It wasn't huge. It looked vintage and might have been custom made.''