Billy Porter Learns the Truth About a Family Murder in New Season of Who Do You Think You Are?

Billy Porter is among six stars who will be diving into their family's past in the long-awaited return of Who Do You Think You Are?

In PEOPLE's exclusive look at the NBC show's new trailer, the Pose star, 52, meets with a family historian and genealogist to learn more about the death of his maternal great-grandfather in 1923.

Through their research, Porter discovers that his great-grandfather was only 33 when he was shot by a police officer, who was never held accountable for his actions.

"Billy's research takes him through conflicting accounts of what happened, before he discovers a local African-American newspaper that lays bare the appalling truth of his grandfather's death and the community uproar that followed," reads a press release from the show.

In addition to Porter, the new season will feature Allison Janney, Bradley Whitford, Nick Offerman, Zachary Levi and Zachary Quinto.

Harris Khan/NBC Billy Porter in Who Do You Think You Are?

RELATED: How Billy Porter Overcame Childhood Abuse to Become a TV Trailblazer: 'My Voice Saved Me'

As seen in the trailer, the celebrity guests will each go on their own journey to discover more about their roots. Along the way, the stars will learn new tidbits of information by using cutting-edge research tools and billions of digitized records from Ancestry.

"Were they running from something or to something?" Whitford, 62, asks in the clip.

A stunned Offerman, 51, also struggles to grasp the truth of his familial history, which extends as far back as the Revolutionary War. "How could all of these family members condone this behavior?" he asks.

In one part, Levi, 41, appears to be shocked as he reads a document, presumably about his relative, who was found "guilty of witchcraft."

Never miss a story — sign up for PEOPLE's free daily newsletter to stay up-to-date on the best of what PEOPLE has to offer, from juicy celebrity news to compelling human interest stories

"All of the dysfunction in our lives, you can trace through your lineage," he later says.

Toward the end of the trailer, Quinto, 45, reveals, "I feel like a much more complete version of myself."

"These are the shoulders that I stand on," Porter adds while holding back tears.

NBC Who Do You Think You Are?

The Emmy Award-winning documentary series, which made its American television premiere in 2010, returns to NBC after running for several seasons on TLC.

Lisa Kudrow and Dan Bucatinsky are serving as executive producers. Porter's episode is set to air first, followed by Offerman, Janney, Levi and Whitford. Quinto's episode will close out the season on Aug. 14.

"Just like each unique episode of Who Do You Think You Are?, our series has been on an unpredictable journey — delayed by the pandemic, yes — but never waning from our mission to tell powerful, personal and global stories," Bucatinsky tells PEOPLE in a statement. "The series has been a true passion project for me and Lisa Kudrow since we premiered on NBC over ten years ago. Our love for and dedication to these moving stories about the shoulders on which so many of our favorite celebrities have stood has only grown over the almost 80 episodes we've made.  Each is a reminder of the enormity of history — but also how intricately and intimately it has foreshadowed the lives of those who come after."

"We're thrilled to be back home, where we began, at NBC: making history by talking about it," Bucatinsky adds. "And we've never been more excited about a collection of ancestral stories than we have with Billy, Bradley, Allison, Zack, Nick, and Zachary."

Who Do You Think You Are? premieres Sunday, July 10 at 7 p.m. ET/PT on NBC. Episodes will stream on Peacock the following day.