WATCH | Celebrities have a tough enough time making a name for themselves in show business, so imagine what it feels like when they're mistaken for another celebrity.
Katy Perry and Zooey Deschanel have blue eyes, a passion for music and perhaps the same face.
Deschanel once asked Perry if their Halloween costumes should be the twins from "The Shining."
Jessica Chastain and Bryce Dallas Howard may have an even closer resemblance.
WATCH | In 2015, Chastain told Jimmy Fallon that early in her career, when fans on New York City's subway mistook her for Howard, she went with it rather than ruin their enthusiasm.
"As one does, I pretended I was Bryce," she told Fallon with a laugh.
WATCH | Howard taped herself lip-syncing to a YouTube video "Jessica Chastain: The Musical," which spoofs the mixup through song. In the video that's collected more than 324,000 views, actress Stephanie Koenig plays Howard, who acknowledges the similarities, yet insists, "I am not Jessica Chastain."
Chastain later posted Howard's lip-dub on Instagram, perhaps adding to the confusion.
The internet doesn't just think Nick Nolte and Gary Busey are lookalikes.
WATCH | With more than 40,000 views, a 2010 YouTube video posted by WatchMojo.com wonders if the similarly intense septuagenarian actors really are two different people:
"Could these two pissed-off, down-and-out, leather-faced men actually be one and the same?"
Sometimes, all it takes to inspire a resemblance is a change in hair color.
A blond Sophie Turner bears a striking resemblance to another 20-something actress ...
... one named Dakota Fanning.
In "A River Runs Through It," Brad Pitt looked a lot like a younger version of his director.
That director? Academy Award winner Robert Redford.
WATCH | They made the Pitt foreshadowing even clearer when they co-starred with each other in the 2001 film "Spy Game."
Even gender isn't a prerequisite for lookalikes. Consider Elijah Wood and Mischa Barton.
But a young Christopher Walken and Scarlett Johansson may be the most shocking doppelgängers.
POLL | Now it's your turn to weigh in. Which of these seven celebrity pairings look the most alike?
Vote in Circa's poll and explain your answer in the comments section below.