Lemon goodness cake

I saw this cake over at another blog and can't wait to make it!

Cake:
1 pkg. white cake mix (and ingredients to prepare according to mix directions)
1 fresh lemon, zested and juiced
1/2 can lemon pie filling

Frosting:
1/2 can lemon pie filling
1 (8 oz.) tub cool whip, thawed
1 lemon, zested and juiced

Heat oven to 350. Prepare the cake according to the box and add in the lemon zest and juice. Put 2/3 of the cake batter in the bottom of a greased 9x13 pan. Drop small spoon fulls of lemon filling into the batter (remember to only use half of the can). Top with remaining batter. Bake for 25 to 30 minutes and allow the cake to fully cool. Fold together cool whip, lemon pie filling, zest and lemon juice. Spread over cooled cake. Keep refrigerated.