FORMER “Dynasty” vixen Joan Collins may finally shake the “poor man’s Elizabeth Taylor” tag with her latest film role.

Friday, Collins steps in as Fred’s fearsome mother-in-law in “The Flintstones in Viva Rock Vegas,” a prequel to the 1994 live-action film in which Taylor performed the role.

Playing stone-age matriarch Pearl Slaghoople could hardly be considered a career high point for either actress, but many considered la Liz’s portrayal the best thing about the original “Flintstones” movie.

And early buzz on Collins’ campy turn as the overbearing mom is just as promising.

Perhaps the kudos will help salve a wound that must still smart: In the early 1960s, Collins screen-tested for the title role in “Cleopatra” but missed out to Taylor, who received a record-breaking $1 million paycheck and international acclaim.

VIXEN VS. VIXEN

ELIZABETH TAYLOR // WHO // JOAN COLLINS

68 (played Pearl at 62) // AGE // 66

London, England // BIRTHPLACE // London, England

Violet eyes // TRADEMARK // Fake eyelashes

“National Velvet” (1944), “Giant” (1956), “Cat on a Hot Tin Roof” (1958), “Butterfield 8” (1960), “Who’s Afraid of Virginia Woolf?” (1966) // FILMS // “The Bitch” (1979), “The Stud” (1978)

8 // MARRIAGES // 4

“I’ve been prepared to do anything in my career and ending up being in a cartoon doesn’t seem unseemly at all.” // ON PLAYING PEARL SLAGHOOPLE // “She is a woman who is very, very keen on clothes . . . very haute couture in a prehistoric way.”

John Goodman, Rick Moranis, Elizabeth Perkins, Rosie O’Donnell // BEDROCK BUDDIES // Mark Addy, Stephen Baldwin, Kristen Johnston, Jane Krakowski

Makes Fred’s life a misery with non-stop nagging // ROLE // Plays matchmaker between daughter Wilma and Vegas playboy Chip Rockefeller