She and Wilson -- who reportedly met several years ago when he hired her to be his trainer -- are not together, the source says, but he's made it clear that he'll be there for her and, when the time comes, the baby.
"Owen is very involved with the pregnancy," the source explains. "He isn't in a relationship with Caroline, nor do they plan to be in one, but he is very supportive of everything. They see each other and talk often about what they want for the child. Owen is very open-minded about everything and has told Caroline he will do whatever he can."
This will be Wilson's second child. The Wedding Crashers star is already dad to son Robert Ford, 2, with ex-girlfriend Jade Duell.