Hollywood was stunned by the nod for the Newcastle-born star’s portrayal of an alcoholic in To Leslie – which took just £22,000 at the box office.
There is a review into whether a host of big name stars helped her secure it.
A-listers including Gwyneth Paltrow, Kate Winslet, Mia Farrow, Susan Sarandon, Minnie Driver and Edward Norton praised the performance by Andrea, 41, in last October’s low-budget independent drama. Ms Paltrow, Jennifer Aniston, Charlize Theron and Courteney Cox also hosted private screenings of the film.
Many of the names share the same agency as Andrea – admired for Battle Of The Sexes and as Mrs Thatcher in TV film The Long Walk to Finchley, but still largely unknown in the US.
She had not been put forward for a Golden Globe or Critics Choice award, the traditional “route” to the Oscars.
The nomination drew disquiet from observers who believe that black stars Viola Davis (The Woman King) and Danielle Deadwyler (Till) should have made the Best Actress shortlist.
Oscars organisers the Academy of Motion Picture Arts and Sciences is checking to see if rules including a ban on “direct solicitation” of votes from members were broken. If so, the nomination may be scrapped.
One Academy voter said: “You could hear the gasps when her name was read out.” Andrea said last week: “I’m astounded.” Her spokesman declined to comment on the probe.
