New York (CNN) Less than a month before he is set to testify in front of Congress, Michael Cohen, President Donald Trump's former personal attorney, has shaken up his legal team.

Cohen, who has been subpoenaed to testify in mid-February by the Senate Intelligence Committee, will be represented by attorneys Michael Monico, a former federal prosecutor in the Northern District of Illinois, and his law partner, Barry Spevack, according to a statement from Cohen's legal consultant and spokesman, Lanny Davis.

Since last summer, Cohen had been represented by Guy Petrillo, a criminal-defense attorney with strong ties to the Manhattan US Attorney's Office, where he had worked as the chief of the criminal division. That office investigated and charged Cohen with eight counts including tax fraud and campaign finance violations.

Cohen, who was also subsequently charged with lying to Congress by special counsel Robert Mueller's office, pleaded guilty to all charges by both offices. He is scheduled to report to prison for a three-year sentence on March 6.

It was not clear exactly why Cohen replaced his legal team, but the relationship between Cohen and Petrillo had been unraveling for some time, according to a source with knowledge of the dynamic between the two men, and had devolved to a "forced marriage."

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