Blyth, who died of cancer in November 2010, turned Aaron Livesy into one of the village soap's central characters.
Recalling the trauma, Miller told The Sun: "Gavin's death hit everyone very hard. It was such a shock. He got cancer then a month and a bit later he just died.
> Danny Miller to leave Emmerdale after four years
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"He was like a father figure for me. I looked up to him and he helped me play the great storylines. He nurtured me. He was a very talented young man. He was there 24/7 for me.
"He stood by his word and he stood by me and said he'd support me and he did. We all miss him so much."
At last year's British Soap Awards, Miller paid an emotional tribute to Blyth, whose time as boss saw Emmerdale's popularity rocket.
The 21-year-old's final scenes as Aaron air next Thursday (April 5).
> Emmerdale's Danny Miller films final scenes, thanks fans on Twitter
> Emmerdale's Aaron Livesy exit details revealed