Simon Cowell’s girlfriend reportedly fears Sinitta won't "let go of her man".
The British socialite divorced her husband Andrew last year after she fell pregnant with a baby boy following an affair with music mogul.
Simon is known for being close to his "harem" of ex-girlfriends, which includes 45-year-old singer Sinitta.
The musician has been vocal since finding out about the baby news and has even said she'd like to "claim" the role of godparent to Simon and Lauren's child - a comment which is said to have angered the expectant mom.
"[Lauren’s] had a rough few months with her marriage collapsing and a controversial pregnancy - let alone dealing with the fallout from Simon's exes," a source told British magazine Star.
"Sinitta hasn't exactly kept a low profile since the baby news was announced. Lauren has been as accommodating as she can, but it's not nice to be constantly reminded of Simon's past. She feels like Sinitta's never going to let go of her man."
Lauren and Simon's little one is thought to be due at the end of February.
It's Lauren's second child, as she already has a son with Andrew, and apparently she's already given the godmother role some thought.
"Lauren has other people in mind to be her son's godmother - like her sister, Nicole," the insider continued.
"She knows that it's important to be friendly with Sinitta for Simon's sake, but hopes that once the baby comes, she'll realise they need their space."