The Emmerdale star once played a motorbike courier delivering a letter to the Queen Vic in EastEnders.
"I'd grown up watching EastEnders and to suddenly be in the Queen Vic was terrifying," he told The Sun of his small part.
"It was the hottest day of the year and the building was absolutely sweltering. When I walked in dressed head to toe in motorbike leathers I was a bit of light relief.
"Everyone laughed at me. I was all fingers and thumbs and I wanted the ground to swallow me up."
Power added of his ordeal: "I had one line, 'Sign there mate', to Ross Kemp, who said to me, 'It's not as easy as it looks', as I fumbled to get the envelope out.
"I don't know why I deserved that. It was an awful experience."
Dominic Power is currently involved in one of Emmerdale's central storylines in the lead up to the village serial's 40th anniversary in October.
His character Cameron Murray is having an affair with Chas Dingle (Lucy Pargeter).