French confirmed the news on Twitter, posting a picture of herself wearing a cross and her character’s dog collar.
“Hmmm. Somethin interestin [sic] this way comes….,” French wrote.
She added in a further statement: “I’m back in the dog collar, back in the vicarage, and back on your telly as part of The Big Night In. Be there, or go to hell. Literally. I have some sway.”
BBC One’s The Big Night In, which will be presented by Lenny Henry, Matt Baker, Zoe Ball, Davina McCall and Paddy McGuinness, will feature stars performing from their own homes and appearing via video link.
Peter Kay and Catherine Tate are among the names currently scheduled to appear.
French’s Vicar of Dibley return marks the first time in five years that she has portrayed the character. She last played Reverend Geraldine in a sketch for Comic Relief in 2015.
The original series, which began in 1994 and ran for two full series and a number of specials, revolved around a then-novel female vicar who moves to an eccentric Oxfordshire village.
Two cast members from the feted comedy have died since it was last revived. Both Emma Chambers, who portrayed Alice, and John Bluthal, who portrayed Frank, died in 2018. Roger Lloyd-Pack, who played farmer Owen, died in 2014.
The Big Night In will screen from 7pm until 10pm on Thursday 23 April on BBC One.