Performing UAT on Production Server

Hello all,

I am new to this area and would like to post the following question:

Currently there exist only development and production servers thus is it advisable for UAT to be performed on a production server?

Before the Go-Live phase, a round of UAT had been performed on the development server.

A day before system Go-Live, the team had performed a last round of simple testing on production server. All production data had been backed up before the last round of testing commenced.

I would like to see for feedbacks / advices if the practice, as mentioned above, is encouraged?

Thanks in advance.