US Republican Speaker of the House Paul Ryan discovered something that shocked him when he participated in the PBS series “Finding Your Roots”: his 3% Ashkenazi Jewish heritage.

The news “about knocked his head off, to tell you the truth,” show host Henry Louis Gates, Jr. said during a panel about the show at a Television Critics Association event on Tuesday, according to Deadline.

The fifth season of the show, which explores the ancestry of prominent individuals, is set to return to PBS in January. Ryan is slated to take part in an episode titled Roots in Politics, alongside fellow Republican, Sen. Marco Rubio and Democratic Rep.

Tulsi Gabbard.

According to Ryan’s official biography on the House of Representatives website, he is a “fifth-generation Wisconsin native.” Ryan is also a practicing Roman Catholic.

Several prominent figures who have known Jewish heritage are also set to take part in the upcoming season, including actor Andy Samberg, comedian Sarah Silverman (whose sister, Susan, is a rabbi living in Israel) and Facebook executive Sheryl Sandberg.

Previous seasons of the show have featured comedian Amy Schumer, actress Scarlett Johansson, actor Paul Rudd and Democratic Sen. Bernie Sanders, who all have Jewish ancestry.

“I find it inspiring that our fellow Americans are so determined to explore their own ancestral heritage,” said Gates in a PBS statement on Tuesday, “precisely at a time when immigration has become such a deeply controversial and sensitive matter. Our series demonstrates each week, in vivid detail and with moving storytelling, that a continuing source of strength for our country is the fact that we are a nation of immigrants...

I believe that the more each of us understands about where we came from, about what our ancestors experienced and how those experiences have shaped us – whether we knew about them or not – the more richly we can live our lives.”