Prepare an 8x8 pan by lining it with aluminum foil and spraying it with cooking spray.
Put white chocolate chips and sweetened condensed milk in a large microwave-safe bowl.
Microwave in 30-second intervals until melted, stirring often.
Split the mixture into two bowls.
Add red velvet cake mix to one bowl and white cake mix to the other.
Stir in cake mix until smooth.
Pour the red velvet fudge mixture into your prepared pan. Shake it gently to even the layer out.
Pour white fudge mixture over top, carefully smoothing it.
Evenly add sprinkles over top.
Chill for 1 hour or until fudge is set.
Lift fudge out of the pan, cut, and enjoy!