Jennifer Lopez and Ben Affleck are making it difficult for observers to call them anything more than "just friends."

The 51-year-old international superstar and the two-time Oscar winner are said to be toeing the line after they were spotted vacationing in Montana over the weekend.

In pictures obtained by the Daily Mail, the pair was seen driving together in an SUV with Affleck at the helm and Lopez riding in the passenger seat.

According to Page Six, a source said the formerly engaged pair were in Montana attending a party of sort. Furthermore, TMZ reported, citing insiders on Monday, that the "Hustlers" actress and "Argo" performer stayed at the Big Sky Resort and had flown out of Bozeman, Montana to the Signature terminal at LAX on Sunday.

JENNIFER LOPEZ, BEN AFFLECK'S RECENT GET-TOGETHERS HAVE BEEN 'FRIENDLY,' NOT ROMANTIC: REPORT

Jennifer Lopez and Ben Affleck

The singer-actress and the actor-director were engaged from 2002 to 2004 and at the time were famously dubbed 'Bennifer' by the media. (Getty Images)

From there, the gossip site said the two hopped in another SUV and drove to Lopez’s Bel-Air mansion – the same residence where Affleck had been chauffeured to on a few occasions in recent weeks.

"Ben and Jen spent several days together in Montana," a source told Us Weekly on Monday. "It was just the two of them on vacation together. Big Sky is a special place to Ben."

The source added that "they looked very happy together" on the trip.

Reps for Affleck and Lopez did not immediately respond to Fox News’ request for comment.

JENNIFER LOPEZ AND BEN AFFLECK ARE 'FRIENDS' AMID RECONCILIATION RUMORS: REPORT

The singer-actress and the actor-director were engaged from 2002 to 2004 and at the time were famously dubbed "Bennifer" by the media. It appears the moniker may make its long-awaited return as it’s been some 17 years since the exes’ initial split.

Lopez recently ended her engagement to former MLB star, Alex Rodriguez, in April after four years together.

Ben Affleck and Jennifer Lopez were spotted vacationing in Montana over the weekend.
(AP, File)

Recently, Affleck praised his ex in InStyle magazine's May issue. "I thought I had a good work ethic, but I was completely humbled and blown away by what she was committed to doing day in and day out, the seriousness in which she took her work, the quiet and dedicated way she went about accomplishing her goals, and then how she would go back and redouble her efforts," he described.

JENNIFER LOPEZ, BEN AFFLECK HAVE MEETUPS AMID ALEX RODRIGUEZ SPLIT: REPORT

"She remains, to this day, the hardest-working person I've come across in this business. She has great talent, but she has also worked very hard for her success, and I'm so happy for her that she seems, at long last, to be getting the credit she deserves," Affleck added.

Lopez shares 13-year-old twins, Max and Emme, with ex-husband Anthony, while Affleck shares three children, Violet, 15, Seraphina, 12, and Samuel, 9, with ex-wife Jennifer Garner.

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Meanwhile, Affleck recently split with actress Ana de Armas in January.