The couple could hardly contain their mirth as they stepped out of London's Claridges Hotel - where they were having dinner with friends - for a cigarette break, collapsing into fits of giggles.
While much has been made of the age gap between the pair, it hardly seems an issue between Katia, 21, and Ronnie, who turned 62 last month. The pair clearly have lots in common and enjoy clubbing as much as they like to share quiet nights in.
Former waitress Ekaterina, who shares a rented house in London with Ronnie, has been a presence in his life since last July when they spent a week together at his home in County Kildare, in Ireland.
After their relationship came to light Ronnie's 23-year marriage to Jo Wood collapsed. They're currently finalising divorce proceedings.
Following a period of adjustment, Jo has said she's in a good place right now, and wants to stay on good terms with her estranged husband.
"I still want us to get on for the children's sake. I want us to be able to have a laugh together," she said. "He’s kind of done me a favour. I'm a lot happier now and feel as if I've got my life back."