Beam me up, Teri Hatcher! The "Lois & Clark" star will make her "Supergirl" debut in "Star-Crossed," tonight's episode. In a new clip, Hatcher's character -- described as "a new villain" in the episode synopsis -- introduces herself to Kara, but seems much more interested in Mon-El.

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The clip opens with a tense sense between Mon-El and Supergirl, where Mon-El offers to be transported onto a mysterious ship in Supergirl's place. Mon-El insists he'll be fine, though Supergirl's worry is evident. So, just as Mon-El is about to be teleported on board, she super speeds into his arms. As such, they're both brought up to the ship -- and Mon-El is none too pleased about it.

Now on board, Mon-El and Supergirl are confronted with a dozen hooded figures. Supergirl immediately goes on the defensive, but is surprised when they all begin to kneel. Confused, she asks Mon-El why they're bowing, only for two unmasked characters -- played by Hatcher and "Hercules" star Kevin Sorbo -- to call out Mon-El's name. The clip ends before Mon-El or Kara are offered the chance to react to it.

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The episode will also lead into the musical crossover episode with “The Flash.” A promo for the episode also reveals the true identity of Mon-El, who had been masquerading as a lowly servant since his arrival on Earth in the Season 2 premiere.

According to the synopsis for "Star-Crossed,"

TERI HATCHER (“DESPERATE HOUSEWIVES,” “LOIS & CLARK: THE NEW ADVENTURES OF SUPERMAN”) AND KEVIN SORBO (“HERCULES”) GUEST STAR; DARREN CRISS (“GLEE”) MAKES HIS DEBUT AS THE MUSIC MEISTER – A new villain (guest star Teri Hatcher) comes to National City, putting Supergirl (Melissa Benoist) on high alert. Meanwhile, Winn’s (Jeremy Jordan) girlfriend, Lyra (guest star Tamzin Merchant), gets Winn in trouble with the law. Maggie (Floriana Lima) attempts to help Winn but old loyalties get in the way. The Music Meister (Darren Criss) attacks Supergirl. John Medlen directed the episode written by Katie Rose Rogers & Jess Kardos. Original airdate 3/20/2017.

Starring Melissa Benoist as the Girl of Steel, “Supergirl” airs Mondays at 8 pm ET/PT on The CW. The series also stars Mehcad Brooks as Jimmy Olsen, Chyler Leigh as Alex Danvers, Jeremy Jordan as Winn Schott, David Harewood as Martian Manhunter and Chris Wood as Mon-El.