The Uncut Gems actor, 32, brought her toddler son to the Elena Velez fashion show at Chelsea Factory on Friday night (9 September).
Fox wore head-to-toe black for the occasion, with a black pleather dress and thigh-high black pointed boots.
She finished off the look with her signature extended wing eyeshadow in a red shade.
Meanwhile, Valentino wore a black romper in a similar texture to his mother’s dress, and tiny black Crocs.
Fox shares her son with ex-husband Peter Artemiev, whom she married in 2018 and separated from in 2020.
On the same night, Fox swapped her goth look for a translucent pearl-coloured dress covered in silver hardware by up-and-coming designer Joanna Prazmo.
She wore the dress to attend the annual Harper’s Bazaar Icons party, which marked the 150th anniversary of Bloomingdale’s this year.
True to Fox’s quirky style, the actor accessorised with a clutch and boots wrapped in clingwrap up to her knees.
Fox opened up about becoming a parent earlier this year, telling People: “[Valentino’s] amazing. He’s my little angel. I love him so much.”
She added that she was keen to have more children and that her son “is ready for siblings”.
In August, Fox – who had a brief whirlwind romance with rapper Kanye West at the start of 2022 – sparked controversy after she advised parents to buy their children cleaning tools instead of toys.
In a video posted to her TikTok on Monday (22 August), she said: “I think that the idea of childhood was invented as a way to just get parents to spend a lot of money on s*** that’s…not really teaching your kid anything.
“You just end up kind of raising a kid that’s like helpless and doesn’t know what to do.”
Fox added: “I found that with my son, he doesn’t care about his toys, and he is actually more interested in like what I’m doing
“So I suggest that everyone buy their kid a mini-mop and mini-broom and start teaching them those life skills really young, so when they enter the real world they don’t have to outsource for everything.”
Her unorthodox suggestion sparked debate among her followers, with some praising her and agreeing with her advic. Others disagreed, arguing that toys were a good thing.