The cast and crew set up camp in Manhattan and shot a few takes.
Mariska, 55, was spotted hanging with castmates Peter Gallagher, Ice-T and Kelli Giddish.
Peter, 63, looked dapper in a blue suit and red tie. The O.C. alum has guest-starred on the series as Deputy Chief William Dodds since season 16.
The cast has been hard at work filming the beloved crime drama since last month.
The actress rocked her classic Olivia Benson costume. She sported tight black pants, leather ankle boots and a dark teal tween blazer.
Season 21 of Law & Order: Special Victims Unit premieres on September 26 on NBC.
Are you looking forward to watching Law & Order’s next season? Sound off in the comments below!