Add pesto, tomatoes and dried basil. Stir to incorporate.
If sauce seems thick or not enough to coat pasta, add tomato sauce a few spoons at a time until desired consistency is achieved. (If using regular pesto, add a bit of olive oil.)
Allow to heat over low heat approximately 8 minutes, or until heated through.
Stir in Parmesan cheese prior to serving.
Notes
For a heartier meal, add 2-3 cooked, diced chicken breasts to the fettuccine prior to serving.