Aside from Moriarty (Andrew Scott), there are also other characters that may be making reappearances in the upcoming fourth season of "Sherlock."

Janine (Yasmine Akram), who was introduced as Sherlock's (Benedict Cumberbatch) temporary love interest, will be returning, according to Latin Times. Janine, who was Mary's (Amanda Abbington) bridesmaid in "The Sign of Three" and the secretary of Magnussen (Lars Mikkelsen) in "His Last Vow," will make friends with the famous sleuth even after their not so-good final encounter last season, according to series' co-creator Steven Moffat.

In Season 3, Sherlock had a relationship with Janine and kept her at arm's length the entire time so he could break into Magnussen's office. Sherlock pretended that he worked during night shifts, so he could not engage in any sexual acts with her. During their final encounter, Janine found out that the detective had lied to her. But because she had made a lot of money from appearing on different chat shows to talk about their relationship, she seemed to have no hard feelings with Sherlock.

"He likes her, though," Moffat told IGN in February about Sherlock's affection towards Janine. "He'll see her again. They'll be pals."

"I loved Yasmine's performance as Janine -- she still likes him in the end," he added. "At some point, you know, if Sherlock Holmes has to go to a function and he needs a date, he'll phone her up. Now, he'll not expect her to say no. She'll be very cross with him, but she'll show up, and they'll have a good time. They will, because he likes her."

Irene Adler (Lara Pulver), another female character who also fell in love with Sherlock, may also be coming back.

Irene last appeared in the flesh when she was being rescued by Sherlock. Since several parties wanted her dead, it was assumed that she had disappeared into hiding. But given her unique relationship with the detective, it has been speculated that she will not be staying away forever, Fashion & Style reported.

"She was terrific fun," said Cumberbatch told Radio Times last year. "She was so brilliant in [Season 2] and we'd love to have her back. Maybe not in this series [Season 3], but she's a great strong character, even though she only appeared once."

Series' co-creator Mark Gatiss, on the other hand, seemed to have a different view on the character's possible return. "The danger is you have a successful character like Irene Adler and she makes a massive impact because that story is so perfect, but if she then moves in around the corner, it becomes a bit cozy," he told Digital Spy in December.

The three-episode Season 4 of "Sherlock" is set to be aired in early 2016, following a full-length Christmas 2015 special, which will go into production in January 2015.