The hats ignited a flurry of criticism on social media, with many calling out the actress and her family for their apparent political getsure.
But now, Sydney has taken to Twitter to set the record straight, explaining that the celebration was completely “innocent.”
"You guys this is wild," she wrote.
"An innocent celebration for my moms milestone 60th birthday has turned into an absurd political statement, which was not the intention.
"Please stop making assumptions. Much love to everyone and Happy Birthday Mom!"
Her brother also confirmed that the hats were not in fact Trump merch, just inspired by his election slogan.
Instead, the hats said, “make sixty great again.”
However, the tweet didn’t seem to halt any criticism, with many arguing that it was just as wrong to use the Trump slogan as inspiration when his far-right politics were so harmful and divisive.
Other fans also pointed out that a guest at the party was wearing a blue lives matter shirt - which is a pro-police countermovement against the Black Lives Matter movement.
“Your fans being hurt that you posted photos of you with your dad in a blue lives matter shirt at a maga themed birthday party isn't unreasonable, girlie.
"Your family looks pretty racist and maybe you should take a second to think about how you're going to address that” explained one Twitter user.
“I dunno why yall think you can wear Trump merch without it being political,” wrote another.
“Except there’s nothing “innocent” about condoning racism and political figures that slander minorities and marginalized groups” commented a third.
A number of fans did come to the actress’ defence, arguing that it was her family - not her who were wearing the shirt and hats.
“Has the thought crossed anyone’s mind that it’s possible Sydney Sweeney strongly disagrees with the politics of her parents, just like an enormous proportion of Millennials/Gen Z?
"She isn’t responsible for her family’s ideas anymore than you are. Leave her alone,” wrote one passionate fan.
But others argued against the defence, explaining that “if Sydney Sweeney disagreed with her parents politics she’d say that.
"Notice that she said it was “innocent” instead. Meanwhile the innocence is bigotry.”
Many also took issue with the fact that Sydney herself had avoided posting any political snaps from the party, with one fan explaining that it was “kinda funny how Sydney Sweeney carefully curated her IG post so that none of the MAGA-inspired hats were seen and then her dimwitted brother’s post blew it all up.”