"Ca n't Fight This Feeling" is a power ballad performed by the American rock band REO Speedwagon. The single remained at the top of the Billboard Hot 100 chart for three consecutive weeks from March 9 to March 23, 1985.

Based on this passage, who sings i can't fight this feeling? Let's give stream of consciousness first:
To answer the question, consider the following: "Ca n't Fight This Feeling" is a power ballad performed by the American rock band REO Speedwagon.
So, the final answer is the American rock band REO Speedwagon.