Warning: This Article Contains SPOILERS for Star Trek: Discovery Season 5, Episode 5 - "Mirrors"

Summary

• Star Trek: Discovery's "Mirrors" reintroduces ISS Enterprise, but Ethan Peck as Mirror Spock didn't happen due to availability issues.
• Co-writer Carlos Cisco explains the missed opportunity for Peck's cameo in the Mirror Universe as Spock.
• Discovery's latest episode explores Mirror Universe history when the ISS Enterprise is found in interdimensional space.

Star Trek: Discovery season 5, episode 5, "Mirrors", reintroduced the ISS Enterprise, but co-writer Carlos Cisco reveals why a cameo by Ethan Peck of Star Trek: Strange New Worlds as the Mirror Universe's Spock didn't happen. In "Mirrors", which was co-written by Cisco and Johanna Lee and directed by Jen McGowan, Captain Michael Burnham (Sonequa Martin-Green) and Cleveland Booker (David Ajala) find the Mirror Universe's 23rd-century Starship Enterprise in interdimensional space and pilot it into Star Trek's Prime Universe 23rd century. However, the ISS Enterprise was abandoned, although a plaque told some of the Mirror Universe's history.

In an interview with TrekMovie, Star Trek: Discovery season 5, episode 5 co-writer Carlos Cisco says that Star Trek: Strange New Worlds' Ethan Peck appearing in some fashion as the Mirror Universe's Spock was "considered" but didn't happen. Cisco speculates that "availability issues" may have been the reason Discovery missed out on Peck playing his goateed Mirror Universe Vulcan doppelganger. Read his quote below:

We had considered Ethan [Peck] as Mirror Spock early on but there might have been availability issues, I don’t know.

Ethan Peck did lend his voice as Spock for several episodes of Star Trek: very Short Treks.

What An Ethan Peck Cameo As Mirror Spock In Star Trek: Discovery Would Have Meant

Star Trek: Discovery reveals what happened to Mirror Spock

No Ethan Peck cameo as Mirror Spock in Star Trek: Discovery season 5, episode 5 is, unfortunately, a missed opportunity. Captain Burnham did think of Spock when she was on the bridge of the ISS Enterprise. Michael told Cleveland Booker that she never met Spock's Mirror Universe counterpart, adding that he was "probably just as ruthless" as everyone else in the alternate reality. Ethan Peck appearing either as a hologram or simply via his voice would been a powerful moment for Burnham and for viewers, although perhaps it also would have distracted from Michael's mission of retrieving the next clue to the Progenitors' treasure from L'ak (Elias Toufexis) and Moll (Eve Harlow).

Michael Burnham saw footage of the older Ambassador Spock (Leonard Nimoy) in the 24th century in the Star Trek: Discovery season 3 episode, "Unification III."

Star Trek: Discovery season 5, episode 5 did reveal the fate of the Mirror Universe's Spock. After meeting the Prime Universe's Captain James T. Kirk (William Shatner) in Star Trek: The Original Series "Mirror, Mirror", Spock followed Kirk's counsel to become High Chancellor and institute reforms to prevent the inevitable collapse of the Terran Empire. Unfortunately, Spock's reforms were perceived as weakness and the Vulcan High Chancellor was assassinated. While Star Trek: Discovery season 5 wasn't originally planned as the final season, not getting Ethan Peck to cameo as Mirror Spock is a shame as, in retrospect, it would have been the last chance for a reunion, of sorts, between Captain Burnham and Spock.

Source: TrekMovie.com

New episodes of Star Trek: Discovery season 5 stream Thursdays on Paramount+