Ms Erivo will join Motsi Mabuse, Anton Du Beke and head judge Shirley Ballas for musicals week on Strictly Come Dancing on November 20 and 21 while Craig Revel Horwood is self-isolating. She said: "I'm so delighted to be joining the Strictly judging panel for musicals week. "Musicals have a unique place in my heart, it's such a special way of connecting all art and making it one. "I'm excited to bring my experience to the show and I can't wait to see what the couples have in store this weekend."
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An acclaimed theatre star, Ms Erivo was nominated for best actress in the biopic Harriet, on the life of the slave abolitionist, in this year's Academy Awards.
The actor has appeared in Broadway's revival of The Colour Purple, the Sister Act UK Tour and The Umbrellas of Cherbourg.
Mr Revel Horwood is the latest member of the BBC programme to test positive following a string of absences from contestants in this year's series.
Loose Women star Judi Love, who was the fifth contestant to be eliminated, was the most recent star to have tested positive. Ms Love had been due to perform a cha cha to Physical by Olivia Newton-John during the October 23 show but had to pull out.