The 'Terminator' actor has hired Robert 'Bob' Kaufman, who has already been in touch with his wife, Maria Shriver's legal representative, Laura Wasser, and claims they are "moving forward" with proceedings to end their 25-year marriage, according to gossip website TMZ.
Bob's work in Hollywood saw him negotiate for Jennifer in her 2005 marriage split from Brad Pitt, as well as for Reese Witherspoon and Jessica Simpson.
He and Laura have gone head-to-head in court before, and both of them specialise in keeping stars' splits low profile.
Arnold and Maria separated on May 10 after 25 years together, shortly before the former Governor of California was forced to admit he had fathered a 13-year-old boy with the couple's former maid Mildred 'Patty' Baena.
It is thought the divorce could cost Arnold $200 million if the couple's assets - estimated between $200 and $400 million – are divided evenly, which would make it one of the most expensive celebrity splits in history.
The couple, who have four children together - Katherine, 21, Christina, 19, Patrick, 17, and Christopher, 13 – issued a statement when they split, saying they will continue to share parental duties.
It read: "We are continuing to parent our four children together. They are the light and the centre of both of our lives."