The shot shows the Cruel Intentions actor, 44, sitting on a picnic table in a white T-shirt and a yellow bandana as he leans on his son’s shoulder.
“We had fun,” Ryan captioned the Instagram snap on Sunday, June 23. “@brckhmptn and @travisscott killd [sic].”
The photo was flooded with comments from fans who thought Deacon, 15, was a dead ringer for the 54 star.
“Wow, like father, like son,” one wrote, with another adding, “Ur [sic] kid is your twin!”
Added a third: “Apple doesn’t fall far from the tree!”
Others thought the teenager bore a stronger resemblance to his famous mother, 43, with comments of “Your son looks like the mom. Mini Reese,” and “He is Reese’s twin!”
“I see [Reese] in that smile,” one fan wrote, with another adding, “That boy is the spitting image of his mother.”
Countered one poster: “I know they say he looks like his mom but you guys have the same eyes for sure.”
The former couple, who split in October 2007, also share daughter Ava Phillippe, 19, who has long drawn look-alike comparisons to the Big Little Lies star. (Witherspoon is also the mother of son Tennessee, 6, from her second marrage, while Ryan is the father of daughter Kai, 7, whom he shares with Alexis Knapp.)
Ryan, for one, wishes people would stop with the comparisons for Ava’s sake: He told Entertainment Tonight in June 2017, “I feel like saying, ‘She has her own face.’ Let her have her own face, you know? I mean, it’s weird, because isn’t that obvious? Who else are they going to look like, you know? I always find that such a weird thing, like [Ava] looks exactly like her mother; who else is she going to look like? It’s an odd thing that people fixate on that.”
Sign up now for the Us Weekly newsletter to get breaking celebrity news, hot pics and more delivered straight to your inbox!