The professional dancer, who partnered Lisa when she was a contestant on the BBC ballroom show in 2012, also revealed that the former 'Emmerdale' actress had a new man in her life, who had supported her during her weight loss bid.
“Lisa’s half the woman she used to be,” Robin told Closer magazine.
“She’s always been bubbly and happy, but now she has a real zest for life. I’m so proud of her for dropping the pounds slowly and sensibly, not through a gastric band or some fad diet.”
He continued: “She’s got a new man in her life and they’re really happy together.
“He’s been very supportive. They got together not long before she started losing the weight.”
Lisa went from a size 30 to a 16, losing six stone in the space of 10 months.
She achieved it through embracing a healthier lifestyle, which included giving up alcohol and taking regular exercise, including Zumba and yoga classes.
She decided to make the change when her father had a cancer scare and was diagnosed with Type 2 Diabetes.
She told Bella magazine: “Losing my mum then seeing my dad wired up and nearly losing him and becoming an orphan was a shock to my system.
“I don’t want to be a statistic. I just want my health to carry on, to live my life to the fullest.”