The glamour model has been practicing her vocals ahead of today's (14.07.09) challenge - which will see her testing her vocal chords and judged on a comedic variation of religious song Pie Jesu.
Reading her challenge to the group out loud, Sophie (Dogface) said: "Housemates, for Dogface's challenge, she must attempt to sing the hymn Pie Jesu as performed on 'Big Brother' five by an ex-housemate from that year."
She exclaimed: "I can't f**king sing that!"
After laughter from her fellow contestants, Sophie continued reading.
She added: "The renditions will be judged by the public via Big Brother's website. The public will be asked which rendition they think is best. If the public decide that Dogface's performance was superior to the Big Brother Five housemate, Dogface will win her challenge.
"If the public decide Michelle Bass' performance was the better of the two, then Dogface will fail her challenge."
In preparation for the challenge - dressed in a cassock - the tuneless blonde has performed several high-pitched and screechy versions of the hymn to her fellow housemates.
Shaven-headed Brummie Lisa teased: "Beautiful. It sounds great that. Hold the note... Lovely! You've got it. Oh that is a tune! Oh that's good. How lovely."