Whoopi Goldberg's cameo appearance in the new musical version of 'The Color Purple' was kept top secret until the film's release.

The 68-year-old actress made her big screen debut in the original 1985 movie - based on the novel by Alice Walker - and won an Oscar nomination for Best Actress and it's now been revealed she returned to make an appearance in Blitz Bazawule's new musical take on the story, but the director went to great lengths to keep the cameo quiet.

He told Variety: "We had to be stealthy about her involvement from the beginning. Only key crew were aware that Whoopi was playing the role.

"We also never mentioned her in any press and she remained uncredited for the role."

The actress played the lead role of Celie in the first film, and the character is played by Fantasia Barrino and Phylicia Pearl Mpasi in the new version with Whoopi returning to play a midwife who helps Celie when she gives birth and Blitz says the role was perfect for the returning castmember.

He added: "I always knew I wanted a connection between the original cast of ‘The Color Purple’ and the new cast. The obvious person was Whoopi because she’s synonymous with the title.

"We settled on the midwife because of its symbolic meeting."

Screenwriter Marcus Gardley also explained the meaning of Whoopi's role to the Los Angeles Times, saying: "She’s the one to not only encourage her during the birth, but it’s like she herself gave birth to the role and now we see her passing it down.

"It’s one of the most beautiful scenes because you see [Goldberg] looking upon [Mpasi] with pride and telling her, ‘You can do it'."

Blitz went on to tell Variety about asking Whoopi to take on the part, admitting he was racked with nerves as he made the phone call. He said: "It was probably one of the most nervous calls ever.

"She was warm from the start and then she ended by saying, ‘Blitz, the only way I’m not going to be there is if I get hit by a bus.’ I broke out laughing. It was the best phone call ever."