Fans have long been speculating that someone has a twin in "Pretty Little Liars," since the original plot of Sara Shepherd's books which the Freeform series were adapted from involves Ali's (Sasha Pieterse) twin sister Courtney. But the theory was shelved after the "A'" that was tormenting the Liars turned out to be Ali's transgender older sister Charlotte (Vanessa Ray).

However, the twin theory is revived after King answered a fan's question on Twitter. But she did not specify who among the characters has a twin. The showrunner simply revealed that the twin will be introduced "soon," and fans of the show will be surprised to find out that the clues have been there all along.

King also teased that some of the show's past characters aside from Melissa (Torrey DeVitto) and Lucas (Brendan Robinson) will be back in the upcoming episodes of "Pretty Little Liars" season 6 in some capacity, including Jenna (Tammin Sursok), Jason (Drew Van Acker), Noel (Brant Daugherty), and Wren (Noel Kahn).

Meanwhile, the trailer for next episode titled "We've All Got Baggage" reveals that Emily's (Shay Mitchell) life is in danger after she discovered the murder weapon used in killing Charlotte. This will be the first time that a Liar will encounter the new villain face to face.

The official synopsis for the episode reads:

"As romantic relationships move forward, the Liars investigate a new suspect in the murder case. With Ezra (Ian Harding) back in Rosewood, Aria (Lucy Hale) must tell him the truth about her involvement with his book. Spencer (Troian Bellisario) and Caleb (Tyler Blackburn) deal with a media leak that affects the campaign. Hanna (Ashley Benson) takes a look at her life after an incident at work. Emily gets harassed by the stalker while she continues the search for Sara (Dre Davis). Meanwhile, two lovers finally tie the knot with the help of a special officiant."

The next episode of "Pretty Little Liars" season 6 airs Tuesday, Feb, 23, on Freeform.