Two months before the U.S. Supreme Court considers whether pharmaceutical sales representatives are entitled to overtime pay, plaintiffs lawyers who brought class wage-and-hour claims against GlaxoSmithKline have gained a powerful ally in the case.

On Monday U.S. Solicitor General Donald Verrilli filed an amicus brief supporting the Glaxo sales representatives. The government’s brief argues that the U.S. Court of Appeals for the Ninth Circuit was wrong when it ruled last February that the GSK reps are exempt from Fair Labor Standards Act overtime rules because they qualify as outside salespeople under the law.

The filing came on the last day that the Supreme Court would accept amicus briefs in support on the sales reps, according to one of their lawyers, Michael Pruitt of Jackson White. “We view it as a very good thing for us,” Pruitt said.

Pruitt, who also represented the sales reps in the lower courts, acknowledged that the Obama administration’s position isn’t a big surprise. After all, the Department of Labor lent amicus support to the GSK plaintiffs at the Ninth Circuit, and it backed Novartis sales reps in a similar case. But the solicitor general’s support was not guaranteed, leaving Pruitt “hopeful” that the brief would appear by Monday’s deadline, he said.

The pharma reps have gained additional amicus support in recent weeks, including from the National Employment Lawyers Association and from lawyers representing a certified class that brought similar claims against Johnson & Johnson.

Two weeks ago Novartis agreed to a $99 million class settlement with company sales representatives who sued for unpaid overtime. Last February the Supreme Court refused to grant certiorari to Novartis in its bid to reverse a ruling by the U.S. Court of Appeals for the Second Circuit finding that the sales reps were entitled to overtime.

The Ninth Circuit had ruled for Glaxo just two weeks earlier in the case now before the Supreme Court, setting the stage for the current circuit split. Arguments before the high court are scheduled for April 16, when Thomas Goldstein of Goldstein & Russell is expected to argue for the plaintiffs against Paul Clement of Bancroft PLLC for Glaxo.

Neal Mollen of Paul Hastings, who represented Glaxo in the lower courts, declined to comment. A spokesman for the company did not respond to a request for comment.