LOS ANGELES — Nearly 40 years after first forging their friendship while working together on the nighttime soap “Knots Landing,” actresses Joan Van Ark, Michele Lee and Donna Mills are now more than just friends — they’re a sister act.

At one point in an interview Thursday at the Hollywood Bowl, the three broke into song: Irving Berlin’s campy “Sisters” from the holiday-film classic “White Christmas.”

“The truth is that we are, in fact, sisters,” said Van Ark, who portrayed the sweet but frequently frantic Valene on “Knots,” which aired on CBS from 1979-93.

“And when we’re together,” Van Ark continued, “it’s goofy and fun. We are truly joined soul-to-soul, heart-to-heart.”

Lee, who played the rock-steady matriarch Karen on “Knots,” turned to Mills and asked her, dryly, “Would you like to say anything?”

Mills, who played the conniving Abby on “Knots,” shot back a humorously curt, “No.”

And then they laughed.

“We always meet for dinner,” Van Ark said. “And if we’ve got a special event like this one tonight, then we have all the more reason to do so.”

December will mark the 40th anniversary of the debut of “Knots Landing.”

Mills said the actress-centric series was ahead of its time in terms of female empowerment in Hollywood.

“We were so strong, our characters were so strong, that it was like, ‘Don’t mess with them.’?”

Might there be plans for an onscreen reunion to mark the “Knots Landing” 40th?

Van Ark joked about the characters: “They’ll all have facelifts, I hope.”

— Associated Press