Much like the rest of the cast, Reese, 43, and Zoe, 30, have become close friends since Big Little Lies debuted in 2017.
"Well.. this pretty much says it all. ?I love you, Z?," the Legally Blonde alum wrote alongside a photo of her and Zoë cuddling while filming the HBO hit.
In the photo, the stars are decked out in the colorful outfits that they wore during the disco party episode of BLL — which aired on Sunday, June 30.
Just a day before Reese posted the loving Instagram, she and her husband Jim Toth made the trip to Paris for Zoë and Karl's wedding on Saturday, June 29.
Big Little Lies airs on Sundays at 9pm ET on HBO.
What do you think of Reese's Instagram post of her and Zoë? Let us know in the comments below!