Cowell has gone incognito after the news surfaced about his relationship with Lauren, who is still married to businessman Andrew Silverman.
"She and Lauren have met at least twice. There have been quite a few phone calls between the two," Sunday Express newspaper quoted a source as saying.
"Lauren has come to regard Jen as her only lifeline to Simon. The arrangement has taken a lot of stress out of her situation. Jen has assured her Simon would never, ever leave her and their unborn child out to hang," a source added.
Lopez sympathises with Lauren's situation.
"While Jen isn't altogether comfortable playing sob sister, she's come to understand how worried Lauren is and let her know she will continue to be there for her," a source said.
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