Michelle Williams explains why she got her hair cut. Credit: Michael N. Todaro/FilmMagic

Work in progress! Michelle Williams turned a few heads when she debuted a new punk haircut on Tuesday, April 9, but the 32-year-old Oz the Great and Powerful actress' hairstylist says the look is only temporary. She's actually in the process of growing out her pixie cut.

"It's getting long. It's growing out," Chris McMillan explained E! News. "We're just cutting the underneath. It's called an undercut haircut." 

"That is one way of growing a short pixie haircut out," Williams' hairstylist added. "You cut the underneath layers and keep the top longer."

In November 2011, Williams told ELLE magazine that she was wearing her hair short "in memorial" of Heath Ledger, the late father of daughter Matilda, 7, because he "really loved it." (Ledger died in January 2008 of a drug overdose at the age of 28.)

But Williams told E! News in February 2012 that she was "ready" to grow out her hair long. She added, however, "The mid-stage is insufferable. It's really hard on your self-esteem . . . That's why I've stayed with short hair for so long."

Tell Us: Do you like Williams' new undercut haircut?