The "Desperate Housewives" star had been scheduled to enter her plea in Boston federal court on May 21, but a judge on Monday agreed to move up the hearing because the lead prosecutor will be out of town.
The actress agreed earlier this month to plead guilty to conspiracy to commit mail fraud and honest services mail fraud. Authorities say she paid $15,000 to have someone correct the answers on her daughter's SAT.
Huffman was charged in March along with dozens of other prominent parents and coaches at elite universities. Prosecutors say other parents paid an admissions consultant to bribe coaches to get their children admitted as fake athletic recruits.
On April 8, the 56-year-old actress announced her decision to plead guilty, explaining that she accepts "full responsibility" for her actions.
"I am pleading guilty to the charge brought against me by the United States Attorney's Office," the "Desperate Housewives" alum said in a statement obtained by Fox News.
"I am in full acceptance of my guilt, and with deep regret and shame over what I have done, I accept full responsibility for my actions and will accept the consequences that stem from those actions," Huffman continued. "I am ashamed of the pain I have caused my daughter, my family, my friends, my colleagues and the educational community. I want to apologize to them and, especially, I want to apologize to the students who work hard every day to get into college, and to their parents who make tremendous sacrifices to support their children and do so honestly.
"My daughter knew absolutely nothing about my actions, and in my misguided and profoundly wrong way, I have betrayed her. This transgression toward her and the public I will carry for the rest of my life. My desire to help my daughter is no excuse to break the law or engage in dishonesty," she concluded.
Court documents stated that a cooperating witness met with the actress and her husband, "Shameless" star William H. Macy, at their Los Angeles home and explained to them that he "controlled" a testing center and could have someone secretly alter her daughter's answers. The person told investigators the couple agreed to the plan.
Huffman was arrested and released on a $250,000 bond in March. Macy was not charged.
Fellow actress Lori Loughlin and Loughlin's fashion designer husband, Mossimo Giannulli, are also charged in the scam. They are not among those who've agreed to plead guilty and haven't publicly addressed the allegations.
The Associated Press contributed to this report.