A lavish arrangements are being made at the Sandy Lane Hotel in Barbados and speculation is rife that it could be for Cowell's wedding.
The hotel sources said they were asked to sign confidentiality agreements. However, a senior US legal source confirmed that the pair are due to wed "imminently", reports dailystar.co.uk.
It is also said that they have already received a marriage licence from a Barbados magistrates court.
A special make-up session has been arranged for Lauren as she feels her pregnancy has made her face look too rounded and she wants it to look slimmer for the day.
One of Simon's entourage said: "I haven't heard anything about a wedding. But you never can tell for certain - he's a man who can pull surprises."
A source close to Cowell's legal team also revealed that he worked out the pre-nuptial agreement before Christmas, and made "significant" changes to his will and life insurance policies to provide for Lauren and her baby due in February.
Lauren's divorce from her husband Andrew was finalised Dec 6.
--IANS (Posted on 29-12-2013)