March 21 (UPI) -- Sarah Michelle Gellar and Alyson Hannigan are mourning the death of their former Buffy the Vampire Slayer co-star Nicholas Brendon.

Brendon's family announced that he died Friday of natural causes at the age of 54.

Gellar posted on Instagram a photo of her and Brendon, alongside the text from a moving statement his character Xander made to her Buffy at the end of the series.

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