In today's article from Entertainment Weekly, Alan Tudyk discusses K-2SO:
http://www.ew.com/article/2016/08/10/rogue-one-alan-tudyk
Love this.For all his rough edges, Kaytoo also feels fierce loyalty, Tudyk says, especially toward Diego Luna’s character, Rebel captain Cassian Andor, who cleared the droid’s databanks of Imperial programming and allowed him to break free of service to the galactic dictatorship.
Their friendship goes back long before the start of Rogue One. “They’ve been around. They’ve been together for a while, a couple years,” Tudyk says. “He wants what Cassian wants. He loves Cassian, because he freed him. It’s also more paternal in that [Cassian] gave him life and took away the bonds of his programming.”
Empire's subscriber cover featurin Kaytoo.
Tudyk, who is 6ft tall, had to wear stilts in order to play K2 during most of the shoot. However, there were times when this was not possible. "I was by cliff once and you can't wear stilts there, because you'll die if you make one wrong step," Tudyk recalled. "So they had this backpack, which ended up being known as the backpack of shame...it had this head that was up where (K2's) head should be."
The "backpack of shame", became a source of great entertainment for Tudyk's co-stars. He recalled on particular exchange with Diego Luna, who plays Cassian Andor. "The first time I wore it he goes, 'Alan, it is terrible what has happened. Everyone respected you just a moment ago, now they just feel sorry for you. Could you please take that ridiculous backpack off, it is upsetting the entire crew.'"
... Tudyk recalled. "So they had this backpack, which ended up being known as the backpack of shame...it had this head that was up where (K2's) head should be."
The "backpack of shame", became a source of great entertainment for Tudyk's co-stars. He recalled on particular exchange with Diego Luna, who plays Cassian Andor. "The first time I wore it he goes, 'Alan, it is terrible what has happened. Everyone respected you just a moment ago, now they just feel sorry for you. Could you please take that ridiculous backpack off, it is upsetting the entire crew.'"
You can see Tudyk peeking out from behind the CGd Kaytoo and the extra head floating on a stick above.: