Warning: The following contains SPOILERS for The Guardians of the Galaxy Holiday Special.One fan theory has been confirmed in The Guardians of the Galaxy Holiday Special, with Mantis and Star-Lord revealed to be related, being brother and sister. Filmmaker James Gunn once previously dismissed the idea, which first came up when sharp-eyed viewers noticed a member of the same species as Mantis among the montage of aliens who were romanced by Star-Lord's father, Ego, in a deleted scene from Guardians of the Galaxy Vol. 2. Apparently those viewers spotted more than a simple Easter egg, as other recent revelations suggest Gunn has long been planning to reveal the two Guardians were related.

The revelation that Peter Quill and Mantis are indeed brother and sister comes up early among The Guardians of the Galaxy Holiday Special cast, when Mantis discusses the matter with Drax, who is the only other member of the team who knows her secret. It is because of that relationship that Mantis feels she should do something special for Star-Lord, since the Earth holiday Christmas (which he loved as a child) is approaching. This sets up the action of The Guardians of the Galaxy Holiday Special, as Mantis and Drax travel to Earth to deliver Earth's greatest hero, Kevin Bacon, as a gift to her brother.

Related: What James Gunn's DC Role Means For GOTG 3 & The Holiday Special

How Mantis Is Star-Lord's Sister & Who Was Her Mother?

Guardians of the Galaxy 2 Mantis Ego

The Guardians of the Galaxy Holiday Special confirms that Mantis, like Star-Lord, is a child of the Living Planet, Ego. However, Mantis has kept this fact hidden from everyone except Drax, knowing how deeply traumatized Star-Lord was after his encounter with Ego The Living Planet and the revelation that he killed Star-Lord's mother. Mantis says that does not want Star-Lord to be reminded of that every time he sees her, fearing he might grow to hate her if he knew that she was his sister.

The identity of Mantis' mother may lie in an Instragram post made by actress Jennifer Sharp in 2017. Sharp posted a picture of herself on the set of Guardians of the Galaxy Vol. 2, writing about how "It was an honor to work with Kurt Russell even for a short flashback scene in Guardians of the Galaxy Vol 2 as Mantis' Mom." The post was later edited to remove any reference to the flashback and her character being Mantis' mother, but a capture of the original post appeared on Reddit. This seems to confirm that James Gunn had intended for Mantis to be Star-Lord's sister since the character's introduction.

Why Mantis Being Star-Lord's Sister Is Perfect For GOTG

Guardians of the Galaxy Holiday Special Peter Quill Star-Lord Hugs Mantis

The revelation that Star-Lord and Mantis are siblings is more than just a sweet treat for the holiday season. One of the biggest recurring themes in all the Guardians of the Galaxy movies is the idea that who someone's family is goes beyond bloodlines and parentage - with the Guardians, dysfunctional as they often are, constituting a true family dynamic. While Star-Lord appreciates Mantis' misguided efforts to deliver the perfect gift to him for Christmas, the confirmation that he's not alone is "the greatest Christmas gift I could ever get."

It seems likely that the newfound relationship between Mantis and Star-Lord will be important after The Guardians of the Galaxy Holiday Special and may tie into the mysteries of Guardians of the Galaxy Vol. 3. Disney+ deleted one episode of the series Marvel Legends focused on Guardians of the Galaxy, which reportedly contained a cut scene of Drax and Mantis discussing her parentage. This suggests that the children of Ego (including Star-Lord and Mantis) may be an important part of the Guardians of the Galaxy Vol. 3 story.

Next: How Yondu Can Return In The GOTG Holiday Special (Isn't He Dead?!)

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