The 'Bleeding Love' warbler is in awe of the music mogul's futuristic-looking bachelor pad which she regularly visits before their boozy catch up dinners, but is always mindful of not drinking too much in front of Simon because it would be like getting drunk in front of her dad.
Speaking to the new UK issue of Marie Claire magazine, she revealed: ''He lives in an amazing bachelor pad that feels like a spaceship about to lift off. We go out for dinner and drink wine. I've never got drunk with him though; it's a bit like when you're with your parents and you're on your best behaviour!''
The 27-year-old singer thinks her ''special connection'' with Simon is down to her being the first star from the UK 'X Factor' to conquer the international pop market, although the pair often squabble over the musical direction of her records.
Leona - who was mentored to victory by Simon on the series in 2006 - explained: ''We've always had a special connection. I think me being the first 'X Factor' contestant to go global was a big deal for Simon. He's supportive and makes me laugh.
''We disagree a lot. At the end of the day he's my A&R guy, so he does have a certain amount of say in what goes on my record and we banter - but I usually get a result!''
However, 53-year-old Simon keeps Leona sweet by treating her to expensive one-of-a-kind Christmas presents.
She said: ''He does give good Christmas presents though. He once bought me a little clutch bag with L.L. emblazoned on it - it's like my own personal designer bag!''