Bring a large pot of salted water to a boil and cook fettuccine according to package directions until al dente. Reserve 0.5 cup of pasta water before draining.
Season chicken and shrimp with salt and pepper. In a large skillet over medium-high heat, add 1 tablespoon of olive oil and sear chicken until internal temperature reaches 165°F (74°C). Remove and set aside.
In the same skillet, add the remaining tablespoon of olive oil and sear shrimp until pink and opaque, approximately 2 minutes per side. Remove and set aside.
Reduce heat to medium. Melt butter in the skillet and sauté minced garlic for 1 minute until fragrant.
Whisk in heavy cream and bring to a gentle simmer for 3-5 minutes until slightly reduced.
Stir in parmesan cheese until the sauce is smooth and thickened.
Return the chicken and shrimp to the skillet. Add the drained pasta and toss to coat thoroughly, adding reserved pasta water if necessary to adjust sauce consistency.
Garnish with chopped parsley and serve immediately.