The FBI recorded phone calls involving the celebrities and a cooperating witness, according to the criminal complaint. Representatives for Loughlin and Huffman did not immediately return requests for comment.

Loughlin, best known for her role in the sitcom "Full House," and Huffman, who starred in the ABC hit show "Desperate Housewives," were charged with conspiracy to commit mail fraud and honest services fraud.

The alleged scheme focused on getting students admitted to elite universities as recruited athletes, regardless of their athletic abilities, and helping potential students cheat on their college exams, according to the indictment unsealed in Boston.

Hollywood actresses Lori Loughlin and Felicity Huffman are among at least 40 people charged in a $25 million college entrance exam cheating scheme, according to court documents unsealed Tuesday.

The plot involved students who attended or were seeking to attend Georgetown University, Stanford University, UCLA, the University of San Diego, USC, University of Texas, Wake Forest, and Yale, according to federal prosecutors.

There's no indication that the schools were involved in any of the wrong-doing.

In all, 44 people, some of them college coaches, have been charged thus far.

Prosecutors said the scheme was masterminded by William Rick Singer, the founder of a for-profit college preparation business based in Newport Beach, California.

Parents paid Singer between $15,000 and $75,000 per test for someone else to take the SAT or ACT exams in place of their college-aged sons or daughters, according to the court papers.

Singer facilitated the cheating by advising students to seek "extended time on the exams, including by having their children purport to have learning disabilities in order to obtain medical documentation that ACT," the indictment says.

Prosecutors said Singer used the cash to bribe two people who administered the exams — Igor Dvorsiky, of Los Angeles, and Lisa "Niki" Williams, of Houston.

Dvorsiky and Williams, in exchange for receiving the payments, allowed Mark Riddell, a Florida man hired by Singer, to secretly take the tests or to replace the children's answers with his own, according to the indictment.

Riddell was paid roughly $10,000 per test, money that was often funneled through a charity account set up by Singer, the indictment says.

From 2011 to last month, parents paid Singer roughly $25 million to bribe coaches and university administrators to "designate their children as recruited athletes, or other favored admissions categories," according to the court papers.

In some cases, Singer's associates created fake athletic "profiles" in an effort to improve the students chances of getting accepted by making them appear to be highly successful high school athletes.

WATCH: 50 people charged in college admission scheme