Elizabeth Hurley said her director put her totally at ease for a sex scene in her new flick ... and that director's also a member of her fam -- namely, her son Damian.

The mother-son duo sat down for an interview with Access Hollywood released Saturday when they were asked how it felt to work on a very intimate scene together as mother and son.

If you don't know ... Hurley stars in "Strictly Confidential," an erotic thriller not only directed but also written by her son. In the flick, EH reportedly wears a lot of skimpy clothing -- and, gets hot and heavy with another woman.

Obviously, Damian's got a job to do -- directing all this action -- but, Hurley said it actually made her feel more at ease rather than uncomfortable for her son to be right there on set.

The way Elizabeth explains it, it's nice to have a person behind the camera who has your best interests at heart -- and who will look out for you more than family?

Hurley says that familiarity allowed to her feel more open during those scenes ... calling the whole experience liberating -- probably a bit of a shock for other people who might be mortified of their child seeing them naked. .

In fact, Hurley says she had such a great time working with Damian that she may just do it again ... perhaps a little mother-son bonding via some intense sex scenes.

As for the 21-year-old, Damian says there was no awkwardness in directing his mom -- 'cause they're showbusiness people, and that's just the world they signed up for.