She's everywhere.

Last year, Mary Martello played Mrs. Warren in Shaw's Mrs. Warren's Profession at the Lantern Theater. In her near future are stints as Lady Bracknell in The Importance of Being Earnest, March 14-April 30 at the Walnut Street Theater; and, not stopping to take a breath, Mama Rose in Gypsy, May 18-June 18 at the Arden.

But, but, but before all that, on Feb. 18-19, she's doing Songs My Mother Taught Me at the Studio Theatre, Hamilton Family Arts Center, part of the Arden's cabaret series. "I look back a year ago, when I first said yes to this," she says, "and I think, 'What in God's name am I getting myself into?' " Martell says she'll sing "primarily my childhood songs, songs my mother sang me and I thought she made up, but I did my research and found out, no, these were the Ames Brothers, Jimmie Rodgers, TV shows of the time, and cowboy songs, which she loved, so I'm doing a set of cowboy songs."

Then onward — to Lady Bracknell, then Mama Rose. What's it like to go among such diverse characters? "It's like going from one country to another," she says, "and in each country you have to speak a certain language, and there are certain cultural mores that you follow. And when you leave, you leave those behind."