The Portugal international has been absent for the past three fixtures in all competitions after suffering a thigh injury in Real's 5-0 drubbing of Almeria on November 23.
But manager Carlo Ancelotti revealed last week that the 28-year-old had been progressing well in training and was set to play in the Group B encounter.
It means Ronaldo will now have the opportunity to break the record for goals scored in the Champions League group stages in a single season.
The former Manchester United forward currently has eight goals, which equals the tally also reached by Ruud van Nistelrooy, Hernan Crespo and Filippo Inzaghi in previous campaigns.
Paris Saint-Germain forward Zlatan Ibrahimovic has also bagged eight times in the pool stage, but he has been rested for their fixture with Benfica with qualification already assured.
Real have an unassailable lead in their section and will look to complete the group stages in style against Stale Solbakken's outfit.
'I’d probably pick Cole Palmer alongside Bellingham and Rice in there at the moment. For me, Declan Rice is good enough to play that central midfield role on his own' Thomas Tuchel advised to DROP Manchester City star by England legend
Manchester United staff threatened with sacking for leaked information... in a leaked email
