Demi Moore and Courtney Cox have fans doing a double-take.

On Thursday, Moore, 56, shared a photo of the ladies posing for the cameras and people couldn't help but notice the friends' similarities with their striking dark hair and black-rimmed glasses.

"Are you relatives," one commenter asked.

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"Wow y'all look like twins," echoed another person.

"Sisters," one fan wrote. "Twinning," one person added.

"Demi and Courteney!! You both look like twins," another person wrote.

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"Twinsies and gorgeous," one commented.

For the picture, Moore opted for a black turtleneck tank paired with denim overalls, while Cox, 55, rocked a black button-down with black pants.

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Moore has been gearing up to release her new memoir titled "Inside Out" -- out next Tuesday -- which her publisher has called "deeply candid and insightful."

According to HarperCollins, the actress wrote openly about everything from her "tumultuous relationship" with her mother, from whom she was long-estranged, to her three marriages, among them to Bruce Willis and Ashton Kutcher.

Fox News' Sasha Savitsky contributed to this report.