Nichols is reported to be "in good spirits" with only minor signs of mobility loss
Nichelle Nichols, best known for her role as Lieutenant Uhura in TV's Star Trek, has suffered a stroke.
"Last night while at her home in LA, Nichelle Nichols suffered from a mild stroke," her agent Zach McGinnis wrote on Facebook.
"She is currently undergoing testing to determine how severe the stroke was. Please keep her in your thoughts."
The 82-year-old was handpicked by Star Trek creator Gene Roddenberry to appear in the original 1960s TV series.
Her casting as fourth in command of the USS Enterprise broke many racial barriers, with Nichols becoming the first black woman to share a kiss with a white man (William Shatner) on US television in 1966.
Up until that point, African-American actresses had typically been cast in servile roles, playing housekeepers or maids. Fans of her Star Trek role reportedly included Dr Martin Luther King.
In an updated post on Facebook, McGinnis reported that Nichols was "awake, eating, in good spirits and able to have full conversations."
"Her right side has shown minor signs or mobility loss but she is not showing any signs of paralyses."
"We greatly appreciate all of the love and support her fans are showing at this time."
The original Star Trek series ran for three years and continues to have a cult following.
Nichols went on to star in several Star Trek films, between 1979 and 1991, including The Wrath of Khan and The Final Frontier.
Later in her career, she played the role of Nana Dawson in the 2006 TV show Heroes and made a guest appearance on Futurama alongside fellow Star Trek regular George Takei in 2002.
She remains a working actress, and reported last month on Facebook that she had begun filming a sequel to Surge of Power.
She was scheduled to appear at New Jersey's Eternal Con - dubbed "the Long Island Comic Con" - on 13 and 14 June.