One of the women who accused Alabama Senate candidate Roy Moore of making advances on her when she was a teen and he was a local prosecutor admitted Friday to writing part of the yearbook inscription she'd offered as proof, a new crack in her story that gives Moore an opening to attack her credibility.

roy moore yearobok ap

Beverly Young Nelson now says part of the inscription near Roy Moore's signature was not written by Moore. (AP)

Beverly Young Nelson admitted to ABC News that she added “notes” beneath what she says is Roy Moore’s signature in her high school yearbook – an inscription that she and famed attorney Gloria Allred presented as proof the then-30-something Moore sought an inappropriate relationship with her in the late 1970s. The “notes” below the signature appear to be the handwritten date and location. Nelson still insisted that Moore wrote most of the message.

“Beverly, he did sign your yearbook?" ABC’s Tom Llamas asked her.

“He did sign it,” she said.

“And you made some notes underneath?” Llamas asked.

“Yes,” she replied.

While Nelson did not specify exactly what she added to the inscription, the text beneath Moore's signature reads: "12-22-77 Olde Hickory House.”

During her original press conference with Allred in November, in which she made her original accusation, Nelson read aloud and attributed the entire inscription to Moore, including the date and location.

"He wrote in my yearbook as follows: 'To a sweeter more beautiful girl, I could not say Merry Christmas, Christmas, 1977, Love, Roy Moore, Olde Hickory House. Roy Moore, DA,'" she said.

At the time, Nelson did not admit to writing the date and name of the restaurant herself. The implication was that it had been written by Moore.

Moore tweeted Friday, "Now she herself admits to lying."

In a brief statement Friday, Moore campaign attorney Phillip Jauregi echoed the candidate, saying, "What [Nelson and Allred] said [in November] was either a lie or what they said today was a lie, and the voters are going to have to decide."

Moore has denied signing the yearbook and said he did not know Nelson at the time. Moore went on to become a judge and then the chief justice of the Alabama State Supreme Court.

The Moore campaign has questioned the authenticity of the inscription since the claim surfaced last month.

During a press conference in Atlanta on Friday, Nelson and Allred stood by their claim that Moore himself inscribed a message in the yearbook. But Allred acknowledged the last part, including the date and location, was written by Nelson.

“Beverly indicates she added that to remind herself of who Roy Moore was and where and when Mr. Moore signed her yearbook,” Allred said.

Allred said a handwriting expert named Arthur T. Anthony determined that the signature is Moore’s and released a report of his findings.

“I want everyone to know that I stand by my previous statement that Roy Moore sexually assaulted me,” Nelson said.

Last month, the Moore campaign demanded that a handwriting expert be allowed to review the yearbook.

“Release the yearbook so that we can determine is it genuine, or is it a fraud,” Jauregui said at the time. He repeated that demand Friday afternoon.

Moore, 70, is running against Doug Jones in a bruising special election to fill the Senate seat vacated by Jeff Sessions, who President Trump named attorney general, and then held on an interim basis by Luther Strange. The election is Tuesday.

The Nelson accusation had bolstered claims by other women that Moore sought relationships with teenage girls in the late 1970s. Leigh Corfman claims Moore molested her when she was 14. Another woman claims Moore groped her in his office in 1991.

An update to this story reflects that Beverly Young Nelson admits writing what ABC News characterized as “notes” beneath what she says is Roy Moore’s signature, and that the only notes below the signature are the date and location. Furthermore, the headline on story now specifies that Nelson admits to writing part of the inscription herself, rather than forging part of it. 

Fox News' Alex Pappas contributed to this report.