With one fierce tweet, Ariel Winter's Modern Family co-star shuts down her haters.

There’s one golden rule that the paparazzi seem to be forgetting: you never say negative things about your sister.

And for Ariel Winter and Sarah Hyland, who star together on sitcom Modern Family, it doesn’t matter any less that your sisterly bond is purely fictional.

Image via Instagram.

Sarah Hyland, 26, has revealed that she was recently pestered by paps to "talk s***" about her television little sister.

Winter was recently targeted in the press after she showed up looking slightly overdressed for a screening event in Hollywood.

While her castmates (made up of mostly men, and one child) chose to dress more casual in pants and shirts, the 19-year-old wore a sparkly, fitted cocktail dress.

The dress. And the other clothes that are somehow less important. Image: Getty.

Probably because, it's 2017 and she's allowed to wear whatever she darn well pleases.

And even though the event happened on May 3, it seems the tabloids are still obsessed with it.

"Paps at the airport trying to get me to talk s*** about my girl @arielwinter1," Hyland tweeted yesterday.

"Y'all digging for something you're never gonna get."

Winter was quick to thank her onscreen sister for coming to her defence, tweeting love hearts and "love you" in response.

Sisters have each other's backs. Image via Twitter.

Winter herself has slammed the reaction to her outfit.

"Why TF does anyone care that I didn't dress casual like everyone else for the panel? Why do I have to be like everyone else?" she wrote on Instagram.

"Why can't people just let other people feel good about themselves and do what they want? WEAR WHATEVER YOU WANT PEOPLE!

"As long as you feel good about yourself that's what matters. I know I did."

LISTEN: Another extremely helpful fashion study is here to tell you what you can and cannot wear. Hooray.