The veteran singer is said to have asked for a 32-inch plasma screen displaying the words to 'Let It Snow' during the taping of the Strictly Christmas special.
The lyrics were allegedly displayed across two screens, but Stewart complained that he couldn't see them properly, according to The Sun.
An audience member said: "People were amazed when they saw the words for 'Let It Snow' on the autocue. It's not as if it is a new song Rod hasn't had time to learn.
"Maybe age is taking its toll and he needed a little helping hand."
A BBC insider said: "It isn't usual for guests to ask for help with the words. Rod also requested a screen as he couldn't read the autocue."
Rod Stewart's appearance on the show was also halted five times due to technical issues.
During his performance, he apologised to wife Penny Lancaster, joking: "It's just like my sex life - stop and start."
Rod Stewart released 'Have Yourself a Merry Little Christmas' earlier this week to raise money for the Teenage Cancer Trust.
Watch Rod Stewart perform 'Let It Snow' below: