AceShowbiz - An actress friend of Nichelle Nichols has launched a legal challenge to overturn the decision to appoint conservators to look after her interests, alleging her son has ulterior motives.

In legal documents obtained by TMZ.com, Angelique Fawcette, an actress claiming to be close to the "Star Trek" legend who famously played Lieutenant Uhura in the iconic '60s science-fiction series, alleges Nichols' recent dementia diagnosis is unsound and that her son Kyle Johnson and four appointed conservators do not have her best interests at heart.

A Los Angeles County judge approved Johnson's request to appoint the conservators in May, after he claimed his mother is suffering from dementia that is "impacting her executive functioning" and makes her "susceptible to undue influence".

Last week (end August 12) her doctor, Meena Makhijani confirmed the diagnosis - a conclusion Fawcette rejects as Makhijani specialises as a geriatrician, rather than a psychiatrist.

Fawcette's filing states that the actress, who gave her away at her wedding - is still lucid and capable of performing her regular daily activities - and only needs help with reminders to pay her bills.

Nichols' alleged friend claims Johnson, who does not live in Los Angeles like his mum, has set up the conservatorship in a bid to gain control of his mother's assets - and has produced as evidence a handwritten note she states the star wrote to her son informing him she was changing her will as he had told her, "I can't wait to get rid of this sh*t and sell (your) house and property," on several occasions.

In her filing, Fawcette claims her pal wants to keep living an independent life and handling her own finances. As further evidence she has submitted a 2013 video interview she conducted with Nichols - in which the star said her son was trying to get her to retire, despite her desire to continue touring the world and appearing at Star Trek fan events.

The actress was seen on the red carpet as recently as July, when she attended Comic-Con in San Diego.