Pretty Little Liars has yet another new character coming to Rosewood, and this one most likely spells bad news for the Liars and their loved ones. Who will be guest starring in PLL in an upcoming episode? And what part will she play?

“Excited for @thatmarciaclark to visit Rosewood tomorrow, playing District Attorney Barnes,” PLL showrunner Marlene King tweeted yesterday. “I think we'll share some secrets.”

Marcia Clark is a former L.A. prosecutor who gained national fame for her role as prosecutor in the O.J. Simpson trial. Since her retirement as high-profile prosecutor, she has worked as a special correspondent for high-profile trials on Entertainment Tonight and has published two books. Apparently, now she can add actor to her list of accomplishments.

@imarleneking I'm SO excited to be on PLL!! Can't wait!! #fanofPLL,” Marcia tweeted back, apparently eager to appear on PLL.

The real question is: why does Rosewood need a district attorney? Have state police officers Holbrook and Tanner finally made an arrest in the murder of Detective Wilden? Who have they slapped the handcuffs on? Could it be Ashley Marin, who is looking guiltier by the minute? Or perhaps, Hanna, who was caught trying to ditch the murder weapon in last week’s ep (Season 4, Episode 5: “Gamma Zeta Die”)? Whoever it is, stakes are getting pretty high in Rosewood.

Why do think D.A. Barnes is coming to town? Let us know in the comments below!

Catch the next episode of Pretty Little Liars on Tuesday, July 16, 2013 at 8 p.m. ET/PT on ABC Family.