"It's true that I had to beg her to wear a matching holiday sweater... but isn't it cute?" the actress wrote on the photo of the pair wearing Christmas jumpers from Witherspoon's own fashion line, Draper James.
After posting the photo, fans were quick to point out the uncanny resemblance between Witherspoon and her 21-year-old daughter.
"How is it that Reese Witherspoon's daughter looks more Reese Witherspoon than Reese Witherspoon herself?" one fan commented.
"How did she steal your entire face?" another said.
For years, fans have pointed out that Ava, Witherspoon's eldest child with Ryan Phillippe, is the spitting image of both of her parents.
As the twin comments arise once again, here's a look at Reese Witherspoon's relationship with her three children.
Reese Witherspoon's relationships.
In 1999, Reese Witherspoon catapulted to fame with her role in Cruel Intentions, which she starred in alongside her then-partner, Ryan Phillippe.