"Transparent" season two is packed full of cameos and guest stars -- but none are more surprising than Sia, who actually shows her face on screen.

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The 39-year-old singer, who constantly hides her face behind wigs when in front of the camera, appears as Puppet in episode nine, when three of the Pfefferman women -- Maura (Jeffrey Tambor), Sarah (Amy Landecker), and Ali (Gaby Hoffmann) -- attend Idyllwild Wimmin's Music Festival. Her brief appearance is almost unrecognizable until her distinct voice is heard singing a few lines as she walks past Sarah and Ali. 

The “Man on the Land” episode also features an appearance by creator Jill Soloway and cameo performances from the singer Peaches and the Indigo Girls. Then there are all the guest stars, including Melanie Hutsell (Carol in "Bridesmaids") and the introduction of Anjelica Huston. Both Michaela Watkins and Bradley Whitford --who won an Emmy for his role in season one -- return to the series in unexpected flashback scenes set in 1930s Berlin, Germany.

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“It offsets the misconception that transgender community is a 21st century phenomenon,” co-producer Zackary Drucker tells ET online about the pre-WWII scenes that also introduce model Hari Nef as Tanta Gittel, a Pfefferman family member first referenced in season one.

"Transparent" season two is now streaming on Amazon Prime.