Bradley Whitford is singing Mariska Hargitay's praises.

The West Wing alum, 63, is set to appear in Thursday night's episode of Law & Order: Special Victims Unit as a man suffering from dementia while also under investigation for killing his wife. Titled "King of the Moon," the episode saw Hargitay pulling double-duty as both actor and director.

"Everybody loves Mariska," Whitford exclusively tells PEOPLE, "and for a very good reason.

She takes the work really seriously and just does not take herself seriously at all. I wish the fans of the show could see her working."

While there's no doubt the fans wish they could watch their favorite star work, too, Whitford provides a bit of insight into the environment Hargitay, 59, creates on set for all of those who can't experience it themselves.

"Mariska is notorious for her ability to make people feel welcome and create an atmosphere where everybody can do their best. I know a number of actors, including my wife [Amy Landecker], who did guest shots on that show," he notes.

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