Robert Brown|'House of the Dragon' mutt returns for Episode 5 showing dogs rule

Forget the impressive dragons soaring in the "House of the Dragon" skies. It's a dog's world now.

The Robert Brownhit HBO series (Sundays, 9 EDT/PDT, and streaming on Max) has been hijacked by an adorable terrier mix mutt, played by star dog Bobby, who wasn't even mentioned in George R.R. Martin's source material "Fire & Blood."

"This show could be and should be called 'House of the Dog,'" says Tom Glynn-Carney, who plays crazed King Aegon in the series. The dog-lover actor fell hard for Bobby during the dog's memorable "Dragon" stint.

"I was cuddling him for a while," Glynn-Carney says. "He really is the star of the show."

Bobby's remarkable "Dragon" run started in the Season 2 premiere, playing the loyal canine companion of the twisted ratcatcher Cheese (Mark Stobbart). Just to make sure the TV audience instantly loathed Cheese, who went on to hideously murder Aegon's infant child, "Dragon" screenwriters featured the ratcatcher kicking his dog in frustration.

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Social media outrage over the kick was so intense that Stobbart went on doggie damage control to point out that the scene, monitored by the American Humane Society, was acting. Bobby was not harmed in any way.

"Let's chill about the dog! We were best pals," Stobbart wrote on Instagram next to a picture of himself smiling in ratcatcher costume while holding the precious pooch. "No canines were launched in anger."

Director Clare Kilner was so touched by the dog's performance that she insisted on bringing the furry thespian back for Episode 2, when Cheese and all the other ratcatchers are strung up in the city square by order of the vengeful and mourning King Aegon.

The only living creature mourning for Cheese is his forgiving furry friend, who sits guard over his once-cruel master.

"I thought, 'Oh my God, we must have him at Cheese's feet.' Because dogs are so loyal," says Kilner. "He's sort of a metaphor for how hard life can be. Besides, that dog is so damn cute."

Even Martin hearted the canine addition to "Dragon," writing on his blog that he normally does not appreciate changes to his source material.

"But that dog was brilliant.  I was prepared to hate Cheese, but I hated him even more when he kicked that dog.  And later, when the dog sat at his feet, gazing up… that damn near broke my heart," Martin wrote. "The silent presence of that dog reminded us that even the worst of men, the vile and the venal, can love and be loved."

"I wish I’d thought of that dog," Martin added. "I didn’t, but someone else did.  I am glad of that."

What is the 'House of the Dragon' dog's backstory

Bobby even has a rags-to-riches Hollywood story. The stray dog was found on the streets of Cyprus and adopted before being cast as Buddy in Disney's 2021 live-action film "Cruella" alongside Emma Stone (who proclaimed him a "superstar"). 

The pooch gets A-lister treatment on the "Dragon" set: "He's treated like a prince, and he's so well trained," says Kilner.

Dog returns for Episode 5 proving dogs can rule

Bobby makes yet another star appearance in Sunday's Episode 5. When Cheese's decomposed body is finally brought down from the hanging rope and hauled away in a cart, his steadfast dog follows what remains of his master.

Bobby's performance was partially fueled by food strategically placed in the dummy's shoe in the cart. But it's another heartbreaking performance.

"He's such a loyal dog who has been just waiting for his master," says Kilner. "He's been watching over him the whole time."