Actress Natalie Portman arrives at the 84th Academy Awards in Hollywood, California February 26, 2012.[Photo/Agencies]

Kate Young, the stylist responsible for some of Michelle Williams' and Natalie Portman's most memorable red carpet moments, tops The Hollywood Reporter's countdown of the 25 most powerful stylists in showbiz.

Young earned the honor in part for helping make Portman a red carpet fixture last year while she was pregnant and on her way to winning the best actress Oscar for "Black Swan."

The issue ranks the trendsetters behind the A-listers, including Leslie Fremar at No. 2, whose clientele includes Charlize Theron and Reese Witherspoon.

No. 3 is Petra Flannery, who likes to discover new talent and make them fashion stars. Her roster includes Emma Stone, Zoe Saldana, Mila Kunis and Megan Fox.

Other notables: At No. 11, Jeanne Yang, who styles Katie Holmes so well they have a luxury sportswear collection in their names at Barneys New York; No. 12, L'Wren Scott, who is engaged to Mick Jagger and a favorite of first lady Michelle Obama; and No. 20, reality TV star Brad Goreski, who made the list while his former employer, stylist-turned-designer Rachel Zoe, went from No. 1 last year to off the countdown this year. (THR says she's now "too big to rank.")