A user’s iPhone X Face ID feature seems to have been fooled by his brother, according to a video posted on Reddit.

The clip comes after Apple released the iPhone X on Friday to customers worldwide and a week after the Cupertino company, carriers and retailers in 55 countries began taking pre-orders for the smartphone last Friday.

Users have been testing the Face ID and the setup process, but a new video shows the facial recognition feature was fooled by a user’s brother. The brothers are not twins, but do have some similar appearances.

In the video, the owner of the iPhone shows how he unlocks the phone with the Face ID. He then hands over the device to his brother. The sibling was not able to open the device using the Face ID at first, but it did unlock when he put on his glasses, which looked similar to the owner’s glasses. The sibling was able to unlock the iPhone X with the Face ID twice.

“As you can see we are both not similar looking, our face structures are different too,” the user said in the video.

Reddit users suspected the glasses may have played a part. However, the sibling noted that the owner of the device setup the Face ID using a different pair of glasses that were not similar to the ones seen in the video.

IPhoneX Face ID fail? from iphone

Twin tests with the Face ID have previously shown how the feature can be fooled by another sibling.

Apple said in its keynote in September when it introduced the Face ID that the probability of someone unlocking another person’s device with the Face ID is approximately 1 in 1,000,000, but that number narrows among twins and siblings.

Apple’s Face ID security white paper elaborated on the feature:

“The probability that a random person the population could look at your iPhone X and unlock it using Face ID is approximately 1 in 1,000,000 (versus 1 in 50,000 for Touch ID). For additional protection, Face ID allows only five unsuccessful match attempts before a passcode is required to obtain access to your iPhone. The probability of a false match is different for twins and siblings that look like you as well as among children under the age of 13, because their distinct facial Face ID Security November 2017 2 features may not have fully developed. If you're concerned about this, we recommend using a passcode to authenticate.”

For those who have twins or siblings who look similar to them, using the Face ID might be concerning. Users who are worried about having their sibling unlock their device might have to refrain from using the Face ID and instead relying on a passcode. The Face ID is one of the most important features of the iPhone X, which would make the $999 price too much for a person who cannot use the facial recognition technology on the device.