The hiring of Kirkland & Ellis emerged as Martin Winterkorn on Wednesday announced his resignation as Volkswagen CEO.
On Tuesday, the carmaker admitted that 11 million of its vehicles worldwide run so-called "defeat devices" that cheat emissions tests and put aside approximately $7.2 billion to deal with the potential costs of the crisis.
However, it could face fines of up to $18 billion in a criminal investigation in the United States, as well as possible charges for its executives and legal action from customers and shareholders.
San Francisco-based law firm Girard Gibbs launched a class-action suit Tuesday in the US District Court for the Northern District of California.
Girard Gibbs filed its case "to hold the auto manufacturer accountable for its unlawful conduct that tricked environment-conscious consumers to purchase 'clean diesel' vehicles that tested as low emission but in reality did little to protect the environment from air pollution."
Volkswagen is also under investigation in a number of other countries across the world, from its home market in Germany to South Korea and Australia.
Kirkland & Ellis led BP's defense in the criminal investigation of the 2010 oil disaster, which claimed 11 lives and caused the worst offshore spill in US history.
In November 2012, BP agreed to plead guilty to 14 criminal counts, including 11 for felony manslaughter, and pay $4 billion to resolve the criminal case. BP agreed in July to pay a record $18.7 billion to settle all federal and state civil claims.
