She hasn’t quite caught up with Elizabeth Taylor’s record of eight husbands, but Liz’s contemporary, “Dynasty” vixen Joan Collins, 68, is set to marry hubby No. 5, 36-year-old Percy Gibson, “on Sunday. The rest of the details are private,” Collins’s spokeswoman, Stella Watson, told Reuters on Thursday. Watson declined to confirm reports in the British press that the nuptials would take place at London’s exclusive Claridge’s Hotel in Mayfair or say who was expected to attend, other than Collins’s three children — but not the star’s sister, novelist Jackie Collins. Recently, said Watson, Jackie had “given a wonderful party for Joan in Los Angeles.” The rep also revealed that the bridal gown was designed by the man responsible for the look of Alexis Carrington, the broad-shouldered ice queen Collins played on TV from 1981-1989. “Nolan Miller has designed Joan’s dress — he designed all of her ‘Dynasty’ dresses.” Collins, whose sagging career was revitalized by that prime-time soap, is reported to have met Gibson, a Peruvian-born theater company manager, when she starred in the A.R. Gurney play “Love Letters,” which toured the U.S. last fall. Reuters says he popped the question after a whirlwind courtship of only a few weeks. “Percy is such a special human being . . . more in tune with me than anybody I’ve ever met,” Collins, who was once engaged to Warren Beatty, recently told The London Times. Collins’s most famous husband was probably the late actor Anthony Newley (“Doctor Dolittle,” the 1967 version), to whom she was married from 1963-1971. They had two children, a boy and a girl, Sacha and Tara. Collins’s third and longest marriage (1972-1984) was to Beatles record company executive Ronald Kass, with whom she had a daughter, Katy.