Star Trek cast members and fans are gathering in Seattle to celebrate the popular sci-fi show's 40th anniversary.
Nichols played Lieutenant Uhura in the original Star Trek series
Walter Koenig, Nichelle Nichols and George Takei from the original Star Trek series are among the celebrity guests attending the three-day event.
They will be joined by Jonathan Frakes and Marina Sirtis from Star Trek: The Next Generation and Majel Roddenberry, widow of late series creator Gene.
The first Star Trek episode was shown in the US on 8 September 1966.
The original series ended three years later but subsequently spawned numerous spin-off series and 10 feature films.
The Star Trek 40th Anniversary Gala Celebration and Conference began on Friday with a party at Seattle's famous Space Needle, featuring live music by a Klingon band.
The event will include an awards ceremony at the city's Science Fiction Museum, a co-sponsor of the event, and a reading of a new Star Trek play co-written by Koenig.
On the conference's official website, science-fiction author Arthur C Clarke has paid tribute to Roddenberry and the universe he created.
George Takei and Walter Koenig are also scheduled to attend
"Over the years the sophistication of storylines and special effects has certainly improved," he writes.
"But Star Trek retains its core values - still very much needed in our sadly divided and quarrelling world."
Since spin-off series Enterprise was cancelled by US TV network UPN, there have been no official Star Trek shows made.
However, plans are afoot for an 11th big-screen adventure, to be directed by JJ Abrams of Lost and Alias fame.