Former reality TV celebrity Michael "The Situation" Sorrentino has been indicted for tax evasion, after federal prosecutors accused him and his brother of hiding millions of dollars he made while a cast member of the MTV series "Jersey Shore."

In an indictment obtained and made public by the U.S. Department of Justice on Friday, Sorrentino and his brother Marc each faces nine criminal counts, some of which overlap, and including their alleged conspiracy to defraud the United States.

The new charges expand a case first brought against them in September 2014.

An arraignment is scheduled for April 17.

"Michael Sorrentino will enter a not guilty plea on April 17, 2017, and will vigorously contest the allegations," his lawyer Kristen Santillo said in an email.

A lawyer for Marc Sorrentino did not immediately respond to requests for comment.

"Jersey Shore" ran from 2009 to 2012, featuring 20-something Italian-Americans partying, tanning and complaining about their jobs at a beachfront T-shirt stand.

Now 34, Michael Sorrentino popularized the phrase "gym, tan, laundry" to describe the pre-party routine of cast members.

The Sorrentino brothers were originally charged with trying to avoid taxes on $8.9 million of Michael Sorrentino's income from 2010 to 2012.

Prosecutors said they under-reported income, and claimed millions of dollars of expenses on clothes, expensive vehicles and other personal items as business expenses.

The new indictment accused Michael Sorrentino of evading taxes in 2011 by hiding income, not filing a personal return, and filing a false return for his company Situation Nation Inc.

It also accused him of having on several days in 2011 and 2012 made multiple cash deposits of less than $10,000 in different bank accounts to avoid federal reporting requirements.

Marc Sorrentino was accused of altering books and records of Situation Nation and MPS Entertainment LLC, in which the brothers owned stakes, after receiving grand jury subpoenas.

The brothers' accountant, Gregg Mark, pleaded guilty in December 2015 to filing fraudulent tax returns on their behalf. His sentencing is scheduled for June 15.

Michael Sorrentino faces a maximum 10 years in prison on each of two counts over the bank deposits, and five years for the alleged tax evasion.

His brother faces up to 20 years in prison if convicted for obstructing a grand jury probe.