Allison Williams' brother is constantly mistaken for her husband at red carpet events.

The Girls actress married Ricky Van Veen, the co-founder of website CollegeHumor, in 2015.

But Ricky has such a startling resemblance to her brother Douglas Williams, photographers often confuse the two men, leading to awkward photo captions.

"This happens one 100 per cent of the time," she said during an appearance on Late Night with Seth Meyers on Thursday night (23Feb17), showing the audience a snap of herself and Douglas attending a premiere, in which he was wrongly labeled as Ricky.

"Directly before this photo was taken, we all said in unison, 'This is Doug Williams not Ricky Van Veen'… 'This is my brother not my husband.' And the photographers all said, 'That's not our job.'"

Allison added that Ricky doesn't mind too much about being confused for Douglas, as it means people think he has been attending events with his wife, even though he's really been at home.

"Ricky loves it because he hates carpets, so he loves that he (gets) the credit... He is walking the red carpet, just in my brother's body," she laughed. "We keep it in the family."

While chatting Allison also took the opportunity to discuss her new project, Get Out. Marking Jordan Peele's directorial debut, the horror film follows a young interracial couple who visit the mysterious estate of the girl's parents.

And the 28-year-old has warned moviegoers that the premise of the film is entirely original.

"It is one of the best movie going experiences I've ever had. Forget that I'm in it, because I have to, to survive it. Sitting in the audience, there are cheers, people applaud, people yell things in unison at the screen, it is a very active audience environment and it is so much fun," she smiled.

"In fact, the last screening I went to, I left to go to the bathroom and I was waiting to come back in and I knew when it was in the movie, based on what the audience was doing vocally."