Miller, who plays Aaron Livesy in the Yorkshire soap, appears on Paul O'Grady's Christmas alongside Bette Midler and Cilla Black, on Christmas Eve.
"Danny was pretty nervous," O'Grady told the TV Times. "But that’s because he hadn’t done anything like that before. Of course, he’s plonked next to Bette Midler and he's only 19.
"And I think, what would I be like at 19 on a prime-time television show sat next to Bette Midler? I'd be frozen rigid! But he's just so mature for his years, and a really smashing actor."
A self-proclaimed soap fan, O'Grady commended Miller for his performance as the gay teenager in the ITV show.
"I’m a massive Emmerdale fan," he said. "I love it. And I think what he’s been doing in the show is exceptional. Hats off to him!"
Paul O'Grady's Christmas airs on Christmas Eve at 9pm on ITV1.