Jessica Lange is not only reprising her four previous “American Horror Story” roles in Season 13 — she’s debuting a new one.

When asked on “Good Morning America” on Tuesday what made her want to return to Ryan Murphy’s horror anthology series, Lange said, “It really was just the idea of bringing those four characters back —and one mystery character that I’m not going to [spoil].”

Later in the interview, when Sam Champion prodded Lange to say more about the fifth character, she hinted that fans may have a chance of deducing who it is. “There is a fifth character, but I won’t say who that is, and I’d be curious if anybody can figure it out,” she said.

Lange’s four known characters include Constance Langdon from Season 1, “Murder House”; Sister Jude Martin from Season 2, “Asylum”; Fiona Goode from Season 3, “Coven”; and Elsa Mars from Season 4, “Freak Show.” According to Lange, “Constance was Ryan’s favorite character from the beginning, so she is featured pretty much throughout the whole thing. The character that I really loved playing was Elsa.”

Lange also teased a musical number she’ll perform as “one of the characters” in “American Horror Story” Season 13, without specifying who. “I have to beg, borrow and plead to get anybody to let me sing,” she joked. When Robin Roberts suggested the number could earn her a Grammy and complete her EGOT, Lange seemed to hint that the character won’t be a strong singer. “I’m going to have to find a Grammy a different way.” Champion asked, “You’re not convinced this is the one?” “No, and neither will you when you see it,” Lange said, laughing.

“American Horror Story” Season 13 premieres on FX on Thursday.