Cowell, 54, and his pregnant wife Lauren Silverman, 36, are secretly planning to tie he knot, reported Showbiz spy.
"Simon has told Lauren that his exes will always be a part of his life," a source said.
Cowell allegedly wants his former fiancee and makeup artist Mezhgan Hussainy as well as longtime girlfriends Terri Seymour and singer Sinitta to be bridesmaids at the bash.
"They're planning an intimate ceremony with a yacht reception in Barbados between Christmas and New Year's. Simon wants to be married by the time Lauren delivers the baby - a boy he's already referring to as Simon Jr - in February.