Higuain spent six years alongside Ramos at Madrid before leaving the Santiago Bernabeu in 2013, but the pair will come together again for the Cardiff showpiece on June 3.
But Ramos will put friendship aside as Madrid bid to win back-to-back Champions League titles.
"He's a great friend and we have a great relationship from when he was here," Ramos told beIN Sports.
"But I won't give away peanuts to Pipa inside the pitch."
Madrid advanced to their third final in four years after overcoming city rivals Atletico Madrid 4-2 on aggregate.
Ramos' men lost Wednesday's return leg 2-1 at the Vicente Calderon but still secured a ticket to the Welsh capital next month.
After last week's 3-0 loss, Atletico threatened to pull off an improbable comeback in their final European match at the iconic stadium thanks to quick-fire goals from Saul Niguez and Antoine Griezmann, but Isco's 42nd-minute strike extinguished those hopes.
"Nobody said it was going to be easy. I am proud of this team. When the match got complicated this team showed personality and went for the goal," Ramos said.
"I emphasise the personality of the team after 20 minutes with a very high pressure and we have obtained what we were looking for."