"Rebecca Romijn ('X-Men' movies) has signed to be a series regular on ABC's 'Ugly Betty,' one of the season's few new hits.

She'll play the mystery woman who's been conspiring with Vanessa Williams' Wilhelmina character to take over the publishing company at the heart of the show.

The character to be played by Romijn has already been seen on the show, but in profile and covered in gauze. A different actress has been supplying the voice of the mystery woman.

Variety says Romijn is expected to begin work on Monday. Her first episode should air in time for the February sweeps."

Source