A new app has been released that allows "Game of Thrones" fans to send messages to each other.

Or rather, one message: Hodor.

Building off the popularity of the television series as well as that of the Yo messaging app, developer Tyler Hedrick created an app called "Yo, Hodor."

The app allows users to create a nickname and add their friends who also use the app. The app then simply displays a list of friends. The user can tap any name to send that friend a message. When the message arrives, the receiver's phone will display the word "Hodor" and play a sound clip from "Game of Thrones."

The original Yo messaging app was released in April and experienced a sudden popularity spike around June 18. It was founded on the idea of sending a simple message to get someone's attention. According to the app's creator, Or Arbel, it can even be used to send more complex messages through context alone, like letting a friend know you've arrived at a meeting place or letting a loved one know you're thinking about them.

"We like to call it context-based messaging," Arbel says. "You understand by the context what is being said." 

Hedrick created Yo, Hodor for his own amusement, and to see how quickly he could reproduce Yo's functionality. He originally shared it only with coworkers, but was soon persuaded to make the app publicly available.

"Everyone thought it was hilarious, so I tweeted about it, which ended up getting quite a bit of attention," Hedrick says. "I submitted it to the App Store a few days later."

The app does face some issues with intellectual property which may eventually result in it being removed. Hedrick already had to change the app's icon from a photo of Hodor he did not have the rights to.

Hedrick doesn't own the sound clip from "Game of Thrones" that the app plays as its notification message, but he's hopeful that HBO will be willing to ignore a small fan project.

"I'm not sure what's going to happen," Hedrick says. "But I assume they would give me a cease and desist before trying to sue me."

Yo, Hodor is currently only available on iOS. However, Hedrick says that he would be happy to work with an Android developer to adapt the app for that platform if one volunteers. The original Yo messaging app is available on iOS, Android, and Windows Phone.