Martell Blue Ribbon and Martell Celebrity are both brands under Martell brand, but their differences are as follows:

1. Different grades: Martell with blue ribbon is one of the highest-end products in Martell brand, and Martell with celebrity is a mid-range product.

2. Different years: Martell with Blue Ribbon is usually a mixture of brandy from different years, while Martell with celebrity usually takes brandy from a specific year as the main one.

3. Different tastes: Martell with blue ribbon is richer and more complex, Martell with celebrity is softer and has a certain sweetness.

4. Different prices: Martell with blue ribbon is more expensive than Martell with celebrity due to the difference in grade and quality.