The Hollywood couple appear to have thrown a pre-wedding shindig in Puglia, southern Italy, further fuelling speculation that the big day is this weekend.
According to US Weekly, more than 50 guests, including Justin's Saturday Night Live pal Andy Samberg, were taken to Cala Masciola Beach for cocktails and nibbles under decorative lanterns.
Justin and Jessica, who are being protected by local police and private security, were spotted in casual clothes at the alleged pre-wedding festivities.
Other photos show guests enjoying a lavish picnic at an Italian castle in Brindisi. It was a rustic affair with traditional Italian entertainers and food served in peasant clay pots. How quaint!
"The wedding is happening outside of Naples in a tiny town this week. It is their favorite place, a location that is very special to them," a source told the New York Post.
Justin will reportedly perform a "tongue-in-cheek" wedding dance for Jessica to 'N Sync's hit 'It's Gonna Be Me', according to The Sun.
The pair have been together for five years, and got engaged 10 months ago. We wish we'd got an invite!
Do you have a celebrity story that should be published on TheFIX? Taken a sneaky pic of a star that you want to share with the world? Send your photos, tip-offs and gossip to firstname.lastname@example.org.