This is one the greatest experiences in Tashkent. If you are in Tashkent and there is a show, dont hessitate to get a ticket. I was lucky to get both opera Pagliacci and ballet Giselle the day after. Alisher Navoiy is the only theater outside Russia that is a part of the Bolshoi. If you want to witness world class. dont hesitate and you wont regret. You can buy tickets upfront onsite, there is a ticket sale in the 2 inner pillars outside, look for the small window. Alternatively you can try ticket.uz. but I had no luck with this so I went there and got the tickets 3 days before. Please note, ballet and opera is popular and tickets go fast.