Prepare simple syrup by combining 1/3 cup water and 3 Tablespoons granulated sugar in a small saucepan. Bring to a boil. Once boiling, remove from heat and add the juice of 1 lemon and 1/2 cup fresh basil leaves. Set aside to cool.

In a large pitcher, combine chilled champagne, chilled orange juice, and lemon basil simple syrup (cooled).

Serve in champagne flutes or wine glasses. Garnish with orange and lemon slices and fresh basil.