A member of staff at the Los Angeles house confirmed Mezghan - who got engaged to the 51-year-old talent show judge last year - is living at the home, explaining: "Yes, she is living here. She is here now."
Earlier this week, Simon told a radio DJ he is "not sure" whether he is still engaged to the 38-year-old beauty - and his 86-year-old mum Julie has since revealed she has not seen Mezghan "for months".
When asked about the couple's relationship, she said: "I honestly don't know, I've hardly seen him. I saw him three days last week and he was working constantly, of course, every day in the studio while he was here. I met him briefly for dinner and he didn't discuss anything with me. He's very private, Simon, about his personal life. He won't talk about it, so I'm as much in the dark as everyone else.
"I haven't seen Mezhgan for months - she's been in America all this time and I don't know if she's working or what, because she has her make-up company and is very busy and I've been on holiday, but she hasn't rung me for weeks. Mezhgan used to call me when she first went back to America a couple of times, but she is busy and I'm busy."
- BANG! Showbiz