There are rumours the actress and Justin Timberlake have secretly got hitched during a private ceremony at a friend's ranch in Jackson Hole, Wyoming.
Hollywood gossip columnist Janet Charlton, who has 30 years experience of reporting celeb stories, said the pair "pulled a fast one".
She wrote on her blog on Friday: "A source just told us that Justin Timberlake and Jessica Biel are getting married in Jackson Hole, Wyoming as we write this!
"They pulled a fast one on everybody! They are in the middle of their ceremony at a very fancy private estate and members of the wedding party are staying at the Four Seasons Hotel there."
However she updated the entry on Saturday: "Last night turned out to be the rehearsal dinner and the wedding is actually today."
Representatives for the couple are yet to respond, but reports have been swirling for months that they would wed in Jackson Hole, where one of Justin's friends owns a property.
The area holds special significance to the pair, as it was in the Jackson mountains that Justin proposed in 2011.
Adding fuel to the fire was the fact celebrity wedding cake designer Sylvia Weinstock confirmed over Twitter she was in Jackson Hole at the weekend.
Last week Jessica talked about her wedding during interviews on the promotional trail for her new film Total Recall.
And judging by her comments, it didn't sound like the special day would be any time soon.
She said: "It's very exciting but it's hard to find the time for it! But it's a good moment just to enjoy it."
She added: "I have no idea of what I want. I am one of those people who are not very detailed orientated… I'm more of a big idea person. I will probably give an idea and let it be created.
"I feel like most of my friends, bless them, always go through some sort of something - one day of 'bridezilla'. Maybe it's just part of the experience."
Jessica and Justin began dating in 2007. They split briefly at the start of 2011 but were back together and engaged before the year was out.