Glenn Simpson, the co-founder of Fusion GPS is about to get his day before the House Intelligence Committee.

Fusion GPS is the company that compiled the controversial Trump-Russia dossier that has become the flashpoint for all things Russia probe-related.

There has been some resistance from Simpson, regarding testifying, but a deal has been struck, where Simpson has agreed to a closed door session with the committee.

 An attorney for Simpson said he will not assert his Fifth Amendment rights during the interview, as was done by two other executives from the firm who appeared before the committee last month.

Simpson had been under subpoena by the committee, which is seeking more information on the dossier as part of its investigation into Russian interference in the 2016 election. That order will be lifted at the time of the interview on Tuesday, Reps. Mike Conaway (R-Texas) and Adam Schiff (D-Calif.) said during a joint statement.

After three hours of hammering out the details, a deal was reached.

Simpson’s lawyer, Joshua Levy pointed out:

“He will be able to maintain Fusion GPS’s privileges and honor its legal obligations,” Levy told reporters, referring to Simpson’s firm. “That’s important to the company, which to this point has maintained its confidential relationships with its clients.”

Testifying voluntarily, Levy said, gives Simpson “the ability to appear with counsel, to assert privileges and to answer questions that he chooses to answer.”

There has also been a battle over the financial records of Fusion GPS, as lawmakers seek to get information about who paid for the dossier.

That deal was struck last week.

Peter Fritsch and Thomas Catan, colleagues of Simpson’s, have previously invoked the Fifth Amendment when called by House Intel.

A “Trump cabal has carried out a campaign to demonize our client for having been tied to the Trump dossier,” Levy said at the time, according to Bloomberg News.

“We endeavor to work with all serious investigators who are going to be striking the balance between Congress’s right to information and our client’s privileges and legal obligations,” Levy said at the time. “We’ve done that with other committees, and will continue to do so.”

The dossier was made public in January of 2017, just before the inauguration. It has proven to be, so far, a collection of some things proven false, some things proven true, and other things that are so outrageous, we may not ever get the full story.