The two have built a close relationship over the years, with the former helping the Oscar winner as she established her footing in the industry.
VIDEO: Salma Hayek parties in tiny red-hot bikini
She highlighted that through her latest social media post that compared their equally glamorous approaches toward red carpet styles.
Salma shared a pair of photographs of her recent black gown for the Kering Foundation with Penelope's similarly regal black gown for the Venice Film Festival.
The Frida star's ensemble featured a fur shoulder trim and beautiful necklace to accompany the sheer skirt and ombre effect created with crystals.
Penelope's was on the simpler side, featuring a structured bodice that gave way to a ruffled skirt with white patterned detailing.
Salma shared photos of herself and Penelope in similar black gowns
Where both matched were in the low-cut necklines and flared out at the waist, accentuating their shapes and falling to the floor to make them look all the more grandiose.
"Penelope may not be my twin but she is my style sister," Salma wrote alongside the photos, and their fans quickly began bombarding them with heart emojis galore.
"Both fabulous," one fan wrote, with another simply calling them: "Gorgeous!" Penelope even responded in a comment by deeming them: "Beautiful!!!!"
"I got here with a ticket to make a movie, I had my return ticket, so I was coming here for two months and I didn't know anyone here," Penelope told Ellen DeGeneres earlier on her show.
The two actresses have been close friends for years
"She picked me up at the airport and she said, 'You're not going to a hotel, you're coming to my house because this is hard at the beginning and you're going to feel very lonely.'
"So she took me to her house. That's why now we're like sisters."
Read more HELLO! US stories here
Like this story? Sign up to our newsletter to get other stories like this delivered straight to your inbox.