Joyce Eng for TV Guide:
NYPD Blue alum Sharon Lawrence will guest-star on Rizzoli & Isles as Maura's biological mother, TVGuide.com has learned exclusively.
Lawrence will appear in two episodes in Season 3 as Hope, who gave up Maura (Sasha Alexander) for adoption when she was 18 following her relationship with crime boss Paddy Doyle (John Doman). She's now a prominent doctor and an activist for women's health with secrets of her own...
Executive producer Janet Tamaro previously told TVGuide.com that Maura will be compelled to look up Hope in the wake of her parents' scares. "Now [that we're going into Season 3] you can really get into background, and Maura's is so mysterious. She's going to learn a lot about herself," Tamaro said. "And let's just say if dad dies, dad is the only one who knew who her mother was. ... That's a pretty interesting character. Whoever was involved with Paddy Doyle and had a baby at 18 and is as intellectually gifted as Maura — who is she?"
Source: TV Guide
Personally I think she's a wonderful choice!! Can't wait for season 3!!