For starters, Sophia and Ashlyn attended Cannes back in June, both participating in a panel about uplifting women in sports ... and sitting right next to each other. Sophia posted 4 images from the event, two of which included Ashlyn.

However, in one of those images, Sophia and Ashlyn are both smiling and laughing while Sophia reaches over and grabs Ashlyn's arm.

There's also a pic Ashlyn posted of her and Sophia from the June Cannes trip where she's got her arm wrapped around Ashlyn as they pose for a selfie ... definite signs the two were very comfortable with each other.

Sophia and Ashlyn posed together in July as well ... snapping a pic at the La Copa Mundial Femenina watch party in Los Angeles.

As we reported ... Sophia and Ashlyn are currently going strong. Sophia filed for divorce August 4 and Ashlyn Harris filed for divorce from her fellow soccer star wife, Ali Krieger, on September 19. Ashlyn and Ali have two young kids together.

Shockingly enough, a report from DailyMail claims Ashlyn told Ali their relationship was over only days after returning from Cannes.

Ali has not yet spoken publicly about the split, but Sophia's estranged husband, Grant Hughes, issued a statement of support, telling us, "Grant will always want the best for Sophia, and is supportive of all that makes her happy and fulfilled."