The singer, who wowed the judges on last night's show with her version of 'This Woman's Work', started working with the producer last year after he spotted her on YouTube.
© ITV
"I did some songwriting with him and he said he thought I had potential and he wanted to see how I would handle different circumstances in the studio," she told The Mail On Sunday.
Asked why she hadn't been signed by the producer, Murphy said: "He said my weight might affect me being an artist. He never said it in a horrible way - he just said it was best for me as an artist.
"Adele has been a massive inspiration because she is a bigger girl who has done well. I don't think anyone pays attention to her weight because she is so talented.
"When I was younger I got some stick but now, because I am so passionate about singing, no one ever mentions it. I am comfortable with where I am and I am going to concentrate on my singing, not the weight."
> Amanda Holden feels frozen out of BGT by Alesha Dixon?
Watch Hope Murphy perform 'This Woman's Work' on Britain's Got Talent below:
