The 47-year-old actor performed on his 1998 track "Quiet Please There's A Lady On Stage" for Duncan in front of the mourning congregation, reported FemaleFirst.
Jackman and his wife Deborra-Lee were joined by celebrity friends, including actor Eric Bana and Tottie Goldsmith, and family members.
Duncan passed away at the age of 81 following her battle with a long-lasting illness, on Sunday.