'The Big Bang Theory' Adds Sean Astin & Kal Penn as Guest Stars

Meaghan Darwish
Preview Dimitrios Kambouris and Noam Galai for Getty Images

Make way for more science — CBS's The Big Bang Theory is packing some serious star power in an upcoming episode.

Kal Penn (Designated Survivor) and Sean Astin (Stranger Things) will join the show as Drs. Campbell and Pemberton. Campbell (Penn) and Pemberton (Astin) are physicists who accidentally confirm Sheldon (Jim Parsons) and Amy's (Mayim Bialik) super-asymmetry theory.

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While neither actor may be a scientist in real-life, their accomplishments certainly support their upcoming roles. Penn, who is currently in production on Season 3 of Designated Survivor (which was picked up by Netflix after ABC cancelled it), is also working on a memoir about his years in Hollywood and the government.

The actor, known for his roles in HouseHow I Met Your Mother and the Harold and Kumar films, took a leave from acting from 2009 to 2011 to work with the Barack Obama administration in the White House Office of Public Engagement. During his time in politics, Penn worked with youth outreach, issues surrounding the Affordable Care Act, repeal of Don't Ask, Don't Tell and benefits for veterans. Apart from acting and politics, the UCLA and Stanford University graduate has also taught courses at Penn State and UCLA.

Astin in Stranger Things and Penn in Designated Survivor

Meanwhile, Astin, who has been a well-known name since his days as Mikey in the cult-classic film The Goonies, has gone on to star in various fan-favorite films like Rudy and the Lord of the Rings trilogy. Astin's most recent work includes the lovable role of Bob Newby in Season 2 of Netflix's hit Stranger Things.

Lending his vocals to various animated projects over the years as well as appearing in guest roles for The Strain and 24, Astin has built a large body of work. The actor is currently wrapping up his starring role in Netflix's upcoming family sitcom No Good Nick, in which he'll appear as Ed.

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For now, fans will have to wait for more details about their upcoming episode, but thankfully, in the meantime The Big Bang Theory returns Thursday after its brief holiday hiatus.

The Big Bang Theory, Thursdays, 8/7c, CBS