REBECCA Romijn is joining the cast of ABC’s “Ugly Betty” as a series regular.

She’ll make her first appearance on the series sometime early next year.

On the show, Romijn will be playing a mysterious masked woman who’s been plotting with Wilhelmina Slater (Vanessa Williams) to take control of Mode magazine from the Meade family.

Romijn will be taking the place of a little-known actress (Elizabeth Penn Payne) who, as the mysterious woman, has only appeared on the show wearing giant sunglasses and a surgical mask all season.

Romijn, a former model, has been eagerly trying to expand her acting chops.

Her most notable acting job so far has been as the blue-skinned, shape-shifting villain, Mystique, in the “X-Men” movies.

She had a short-lived show on the old WB network.