Watch Kieran Culkin's real-life siblings play his brothers in “The Second Best Hospital in the Galaxy”

See an exclusive preview of all five Culkin brothers — Kieran, Macaulay, Rory, Christian, and Shane — acting together for the first time in the new animated series.

Who better to play Kieran Culkin’s alien brothers than his real-life brothers?

Prepare to witness a wonderfully weird family reunion: Macaulay Culkin, Rory Culkin, Christian Culkin, and Shane Culkin all lend their voices to an episode of Kieran's upcoming Prime Video animated series The Second Best Hospital in the Galaxy, marking the first acting project for all five brothers together — and just in time for St. Cthonk’s Day.

EW is debuting an exclusive clip of the series (above), which sees empath Dr. Plowp (Kieran Culkin) celebrating a holiday with his colleague Dr. Sleech (Stephanie Hsu), just as their relationship is evolving. As if feelings and a recent trauma aren’t difficult enough for her to bear, there’s also the unexpected presence of Plowp’s siblings. Just like that, the aloof doctor is trapped with five people who are very invested in her emotional state.

“Is this a sex dream or a sex nightmare?” she wonders aloud as she enters the room.

“Why not both?” Dr. Plowp responds. “These are my brothers.”

The exchange of gifts, emotions, and digestive salivas turns out to be a bit much for Dr. Sleech, who quickly runs from the celebration and the couple’s developing relationship. But before she slips down a garbage chute, we get a glimpse at Dr. Plowp’s emotionally attuned family at work.

You can see the Culkin brothers acting together in the clip from the show's sixth episode above.

The series marks a rare onscreen reunion for the Culkin brothers, who have been performing since a young age but rarely share the screen since taking their careers in different directions. The roster of siblings also includes sisters Quinn Culkin; Dakota Culkin, who died after being struck by a car in 2008; and half-sister Jennifer Adamson, who died of a drug overdose in 2000.

When Macaulay’s career first took off in the early ‘90s, he often starred alongside his siblings, sharing the screen with Kieran in the Home Alone franchise, and Quinn and Rory appearing in 1993’sThe Good Son. Rory also played younger versions of his brothers in his early work: as Macaulay in Richie Rich and Kieran in Igby Goes Down. Christian's only onscreen role is in 1994's My Summer Story, alongside Kieran.

TRory and Quinn recently showed up to support big brother Macaulay at his Walk of Fame star ceremony in December.

he Second Best Hospital in the Galaxy follows Dr. Sleech and Dr. Klak (Keke Palmer) as they attempt to cure anxiety, illegal time loops, and deep-space STIs. The series from creator Cirocco Dunlap boasts a star-studded cast that also includes Sam Smith, Maya Rudolph, and Natasha Lyonne, with guest stars such as Tracee Ellis Ross, Bowen Yang, Abbi Jacobson, John Waters, and more.

Get ready to celebrate St. Cthonk’s Day soon: all eight episodes of the show's first season will debut on Prime Video on Feb. 23.

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