Fill a chilled champagne flute with the 2 ounces of champagne.
Shake the gin, lemon juice and syrup in a shaker with ice for about 10 seconds then pour into the glass with champagne. Garnish with a lemon peel.
Note: If you use a Champagne that is on the sweeter side then cut the syrup down to a half or a quarter. If you use Prosecco, you may want to cut the syrup out altogether.