It's rare to see a celebrity go fanatic over another celebrity. But on Maisie William's case, that's what exactly happened.

During a sit-down interview with the hosts of Radio 1 Breakfast Show, Kit Harington was informed that he was going to get a call from his biggest fan in the whole world.

The "Jon Snow" actor was delighted of the feature. He wasn't expecting Williams, who plays "Arya Stark," to call in on the show. But she wasn't about to go fan-girl all over him. Instead she apologized for missing his play. According to CBS News, Williams was so excited that she was able to talk to her co-star. She explained she was coming from the gym and wanted to apologize about missing his play, titled "Doctor Faustus." "I'm really gutted that I didn't get to come see 'Doctor Faustus,'" she said. "I'm so sorry -- I got an ear infection," the young "Game of Thrones" actor said.

To make up for it, she promises to watch another screening of his play, along with Sophie Turner, if they were able to get tickets. "Can you do it on a night where you've got the night off and we can go party afterward?" she asked. Happy that his fellow "Game of Thrones" stars are going to watch his performance, Harington said that coming in on a Thursday or Saturday would be great.

The shows are already booked with "Jon Snow" fanatics but knowing "Arya Stark" may be coming to watch, would mean that the upcoming Thursday and Saturday shows for "Doctor Faustus" will be very popular with "Game of Thrones" fans.