Cara tagged Ashley in the video, and included several rainbow and heart emojis.
The couple, who met last year (2018) on the set of the musical drama co-starring Elisabeth Moss, first sparked romance rumours last August (2018), when they left Kylie Jenner's birthday party together, and fuelled speculation when they were photographed kissing at an airport in London a few days later.
Ashley, 29, was also seen cheering on Cara as she walked in Chanel's Paris Fashion Week show, and at the time, stylist Jamie Mizrahi shared a photo of the duo cuddling up on Instagram.
The women have refused to confirm their romance, despite Ashley being spotted wearing a necklace with the initials "A" and "C".
Cara first came out as bisexual in 2015, and previously dated singer St. Vincent, real name Annie Clark, until they split in 2016 after a year and a half.
"Once I spoke about my sexual fluidity, people were like, 'So you're gay,'" she told Glamour magazine back in 2017. "And I'm like, 'No, I'm not gay.' A lot of the friends I have who are straight have such an old way of thinking. It's, 'So you're just gay, right?' (They) don't understand it."