Lainey Gossip says the pair have been "inseparable" for the last couple of weeks, and the New York Post tracks them from Martha's Vineyard to the Hamptons before they hit Toronto, where the actress is shooting the "Total Recall" remake with Colin Farrell.
They apparently made the most of their Canadian rendezvous.
According to Life & Style, Justin and Jessica were joined at the hip over the weekend, enjoying three low-key trips to a local coffee shop and plenty of face time.
"They seemed so comfortable, happy and at ease every time. They literally couldn't stop staring and smiling at each other," relays an eyewitness. "Justin seemed completely smitten with Jessica, and she had this permanent smile on her face, and they joked around with each other."
For those wondering about their caffeinated drinks of choice (hey, no judgment), Biel stuck close to home with an Americano; Justin opted for a double cappuccino with maple syrup.
The duo, who called it quits in March after four years of coupledom, also hit a café for brunch on Sunday (scrambled eggs for him; omelet for her -- you're welcome).
"They were laughing and having such a good time," an eatery source tells L&S. "They enjoyed their food, but they seemed to enjoy each other much more!"
Adds another snitch to the Post, "They were in baseball caps and sunglasses, but everyone recognized them. Everyone acted very Canadian and left them alone."
Timberlake, 30, who was linked to everyone from Olivia Wilde to Ashley Olsen after he reclaimed his single status, previously trekked up to Toronto in July to visit Biel, 29 (shortly before his visit, she enjoyed a ride on the back of Gerard Butler's motorcycle). The on-off squeezes were also seen taking in an off-Broadway show earlier this month.
But does Justin's willingness to travel mean he's ready to settle back into a relationship with the "most special" and "most significant person" in his life?
Maybe, maybe not.
The Post says that Biel was recently overheard telling pals she was going on vacation with "her boyfriend," but E! News notes there's "nothing official," which is disappointing, because we prefer all our celebrity reconciliations to be accompanied with notarized documentation.