The 44-year-old actress - who dropped from a size 30 to size 14 in just under two years - revealed her 12 stone weight loss was triggered by the death of her mother Cath from breast cancer aged 57, prompting her to overhaul her lifestyle.
Riley told The Sun of 32-year-old singer Adele’s own incredible change in appearance: “It’s as if we are going to forget how many Grammys she has won and all of a sudden go, ‘She has lost an awful lot of weight’. Let’s talk about her talent and how phenomenal she is.
"Of course she looks stunning, amazing and sensational but it’s about how she has turned a corner in her life - just as I did when mum died. I was petrified of developing Type 2 diabetes and I have got a feeling that she will have had some light bulb moment that triggered her, too.”
Adele recently debuted her dramatic new look on social media and her significant weight loss has been credited by her former personal trainer Camila Goodis to a plant-based diet and Pilates. The Skyfall singer split from husband Simon Konecki in April 2019 after eight years together.
Riley - who returned to the role of Mandy Dingle in Emmerdale last year - insisted her weight loss had not changed her as a person.
The soap star said: “I am so proud of everything I have done. At my funeral, the priest is not going to say, ‘Thank you for coming, Lisa Riley was fat!’. He is not going to mention my size, as it doesn’t matter.
“I love the fact I can inspire people to be healthy and make them believe that if they want to make it happen they can. But I have given so much more to people and my career.”
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Riley - who competed in Strictly Come Dancing in 2012 - debuted her weight loss in 2016 having dramatically changed her lifestyle, including giving up alcohol and smoking.
Speaking about losing her mother she said: “People talk about, ‘How can you not eat cake’, but that is easy and a walk in the park. Living without my mum, now that is hard. The fact I can’t ring mum on my birthday kills me. But I feel she is there with me every second of the day and that is how I deal with the daily struggle.”
The actress has been dating fiance musician Al, 49, since 2012 and they have been engaged since May 2018 and had been hoping to tie the knot this year.