Taking to his Instagram, Eamonn explained to his fans in a live chat that there were two reasons why she was overcome with emotion – her father and her sister Julia who passed away last year.
"I just wanted to come on and talk to you and say thank you because earlier this evening Ruth and I appeared on ITV, on the new Alan Carr revival of classic game shows and tonight was Play your Cards Right. It was recorded quite a long time ago and we were sort of watching it as though we didn't know what was going to happen but what did happen is that we won, we didn't just win, we won £30,000 for charity and the charity in question was the Alzheimer's Society."
He added: "Ruth got very emotional at the end of this and there are a number of reasons why she got very emotional, but let's just say the overriding reason is that her father died from this awful condition, this awful disease."
Explaining the second reason, Eamonn continued: "Ruth was very overwhelmed at the end and she broke down in tears, and as I said on Twitter and Instagram, she had a very good reason to weep.
"When this happened there was a lot going on in her life as well, it was the first programme she had done after the death of her sister so there was a big well up of emotions within her," he said.
Ruth's father was 84 when he died in 2012. Speaking of his death on Loose Women back in 2017, she said: "I was grieving and losing my dad but my mum was losing the love of her life, the man she married and had children with. They had years and years of memories. You don't often hear people talking about that side of it.
Ruth with her sister Julia
"When my dad went into care, my mum was so distraught... I'm sorry," she said, wiping a tear from her eye. Ruth continued: 'You do hope, but you know they probably won't get better. I'm sorry, sometimes I just can't talk about it. It's thinking about my mum, that side of it that gets to me."
The This Morning presenter's sister, Julia, sadly passed away in June last year. At a later inquest into her death, it was revealed Julia had taken her own life after suffering with depression for a number of years. She was found by her heartbroken husband Paul at the home they shared together in Lingfield, Surrey.