We're not so sure her disguise was all that convincing – what, no funny nose or glasses to complete the look? – but she certainly looked different with something other than the pixie cut we're used to seeing.
Her TFIOS co-star Ansel Elgort shared the pic of Shailene's undercover look, Instagramming the selfie of the two of them and writing, "Shai's amazing disguise to go see #tfios last night without causing a scene!"
He also tweeted: "Shai is bringing her own popcorn to #tfios hahahaha. So bootleg."
It looks like her undercover plan did the trick and she went unnoticed, but we can't believe someone didn't spot her. And...um...Ansel wasn't wearing a disguise. No one caught on that it was him?