It will be a parents' day unlike any other as a group of wealthy mothers and fathers are scheduled to appear in Boston federal court on charges connected to a nationwide college entrance scam.

At least 13 of the 33 parents indicted earlier this month in the stunning $25 million bribery and test-rigging scandal are expected to enter pleas on charges of racketeering conspiracy.

The parents, including chief executive officers of major companies and two well-known actresses, allegedly paid bribes of up to $6.5 million to William "Rick" Singer, identified by authorities as the ringleader of the scam, to get their children into elite colleges, including Yale, Stanford and Georgetown universities, and the University of Southern California, federal prosecutors said.

The procession of parents ordered to appear in federal court will come one day after a key defendant in the case, Rudolph "Rudy" Meredith, 51, the former head soccer coach at Yale University appeared in U.S. District Court in Boston.

PHOTO: Rudy Meredith, the former head soccer coach at Yale University facing charges in a nationwide college admissions cheating scheme, arrives at the federal courthouse in Boston, March 28, 2019.
Katherine Taylor/Reuters
Rudy Meredith, the former head soccer coach at Yale University facing charges in a nationwide college admissions cheating scheme, arrives at the federal courthouse in Boston, March 28, 2019.

In a prearranged agreement with federal prosecutors, Meredith pleaded guilty Thursday afternoon to charges of conspiracy to commit wire fraud and honest services wire fraud.

He faces a maximum prison sentence of 20 years and a fine of up to $250,000 although prosecutors say they plan to recommend a reduced punishment due to Meredith's cooperation in the investigation. He is also expected to be ordered to fork over to a total of about $900,000 in bribes he accepted, officials said.

Prosecutors said Meredith was paid more than $400,000 in bribes from Singer to accept student applicants to Yale as soccer team recruits even though they did not play soccer. Federal agents, who dubbed their investigation "Operation Varsity Blues" claim Meredith also solicited other bribes on his own, which eventually led to his downfall and prompted the Federal Bureau of Investigation to launch the probe that grew into the largest college cheating scam ever prosecuted by the U.S. Department of Justice.

Meredith, who prosecutors said had been working with Singer since April 2015, resigned as Yale's head women's soccer coach in November after 24 seasons. At the time he said "it is time to explore new possibilities and begin a different chapter in my life."

The Wall Street Journal reported that Morrie Tobin, a Los Angeles financial executive, had sought leniency in an unrelated securities fraud case against him by tipping off federal investigators that Meredith had sought a bribe from him in return for getting Tobin's daughter into the Yale. Tobin's tip, according to The Journal, led investigators to uncover the widespread cheating scandal involving dozens of wealthy parents, including Hollywood actresses Felicity Huffman and Lori Loughlin, and Loughlin's husband, fashion designer Mossimo Giannulli.

PHOTO: William "Rick" Singer leaves the federal courthouse after facing charges in a nationwide college admissions cheating scheme in Boston, March 12, 2019.
Brian Snyder/Reuters
William "Rick" Singer leaves the federal courthouse after facing charges in a nationwide college admissions cheating scheme in Boston, March 12, 2019.

Earlier this week, Yale rescinded the admission of a student that officials at the school say was involved in an alleged college entrance scam. The ousted Yale student's parents had allegedly paid Singer $1.2 million to get her into the Ivy League school, prosecutors said.

Singer has pleaded guilty in a Boston federal court to charges of racketeering conspiracy, money laundering conspiracy, conspiracy to defraud the United States and obstruction of justice.

Tens of thousands of dollars in bribes allegedly went to a sham charity Singer set up called the Key Worldwide Foundation. Singer, according to prosecutors, would funnel the money to those working in cahoots with him, including coaches who listed college applicants as recruited competitive athletes despite some of them never having played sports, according to prosecutors.

Singer also bought off college entrance test administrators and at least one test proctor who allowed Mark Riddell, a private school counselor in Florida, to allegedly take entrance exams for students or correct them on the sly, according to the indictment.

Meredith isn't the only college coach ensnared in the scam.

Pleading not guilty on Monday in Boston were legendary USC water polo coach Jovan Vavic, who has been fired by the school; Laura Janke, the former USC women's soccer coach; former Georgetown University tennis coach Gorden Ernst; former UCLA men's head soccer coach Jorge Salcedo; Wake Forest head volleyball coach William Ferguson, who has been placed on administrative leave; and former USC women's head soccer coach Ali Khosroshahin.

Martin Fox, president of a Houston-area tennis academy pleaded not guilty. Fox, who is also involved in guiding student basketball players to college, allegedly accepted at least $250,000 in bribes to help Singer with both athlete recruitment and test-taking fraud, prosecutors said.

Donna Heinel, the former senior associate athletic director at USC, also pleaded not guilty to racketeering conspiracy on Monday.

PHOTO: An undated photo of Yale University.
STOCK PHOTO/Getty Images
An undated photo of Yale University.

John Vandemoer, the former sailing coach at Stanford University, pleaded guilty earlier this month to racketeering conspiracy in the case.

The parents scheduled to appear in court on Friday include Michelle Janavs, 48, the inventor of "Hot Pockets" microwavable sandwiches and the former executive and founder of her family food manufacturing company; William McGlashan, Jr., 56, the fired senior executive of the private equity firm TPG; Gregory Abbott, 68, the founder and chairman of International Dispensing Corp., a food and beverage packaging company, and his wife, Marcia, 59.

Other parents ordered to appear in court on Friday are former casino executive Gamal Abdelaziz, 62; Los Angeles sales executive Stephen Semprevivo Jr. 53; Napa Valley winemaker Austine Huneeus, 53; San Francisco entrepreneur Todd Black, 53, and his wife, Diana Blake, 55, an executive at a retail merchandising firm; Marjorie "Margie" Klapper, 50, the California co-owner of the California jewelry business M&M Bling; Marci Palatella, 63, CEO of the California liquor distribution company Preservation Distillery; and Robert Zangrillo, 52, a prominent Miami investor and real-estate developer.

Huffman, Loughlin, and Giannulli are scheduled to appear in Boston federal court next month with the remaining parents charged in the probe.

Huffman's husband, actor William H. Macy, was not indicted, but according to court documents he and Huffman were caught on a recorded conversation with a corroborating witness in the case, allegedly discussing a $15,000 payment to ensure their younger daughter scored high on a college entrance exam.

Huffman was indicted on charges stemming from the $15,000 she allegedly disguised as a charitable donation so her older daughter could take part in the college entrance cheating scam, the indictment reads. But Huffman and Macy apparently decided not to go through with the scheme for their younger daughter.

Loughlin and Giannulli are charged with allegedly paying Singer a bribe of $500,000 "in exchange for having their two daughters designated as recruits to the USC crew team -- despite the fact that they did not participate in crew -- thereby facilitating their admission to USC," according to the indictment.

Earlier this week, the U.S. Department of Education sent a letter to the presidents of eight universities linked to the scam advising it has launched a "preliminary investigation" into each of the schools, which also include UCLA, Wake Forest University, the University of San Diego and the University of Texas at Austin, according to the Politico.

Spokespersons for the University of Texas and Yale confirmed to ABC News this week that the presidents of their schools had received the letter and were cooperating with the Department of Education.

ABC News' Victor Ordonez and Brian Hartman contributed to this report.