In her first major solo role without her twin sister, Mary-Kate Olsen is returning to series television for the first time since 2002 with a co-starring role on Showtime’s dark comedy “Weeds.”

Olsen will play Tara, a devoted Christian girl living in the newly developed megachurch community Majestic who becomes a love interest for Nancy Botwin’s (Mary-Louise Parker) son Silas (Hunter Parrish). Olsen will appear in 10 of the 15 episodes of the show’s third season, which premieres August 13.

Since their debut on ABC’s hit comedy series “Full House” at age 9 months, Olsen and her twin sister, Ashley, have starred together in a string of kids- and tween-oriented series and movies for television and video. In 2001-2002 they starred in the ABC Family sitcom “So Little Time.” They most recently starred in the 2004 feature comedy “New York Minute,” which the two also produced.

Olsen’s role on the edgy Showtime series about a pot-dealing mom (Parker) also is a departure from the wholesome, PG characters she and her sister have played and opens a new chapter in her acting career. Olsen’s treatment in 2004 for an eating disorder was widely reported.

“‘Weeds’ isn’t your 8 o’clock family fare,” series creator and executive producer Jenji Kohan said. “It’s an adult show with adult subject matter, and we’re confident Mary-Kate is right for the role. She came in and read with Hunter and was absolutely charming and real and seemed like a great fit. Audiences have seen only one side of Mary-Kate, but here we’ll see her in a whole new light.”

In addition to Olsen, joining the “Weeds” cast this upcoming season is previously announced Matthew Modine.