What is the extent of the Water Damage ??
The first thing to do is limit the damage the water leak is making; this might just be putting a bucket or a towel under the leak. Even if you are going to look and see what the issue is, it is best to put this in place first to limit water damage of the room below the leak.
Be aware that if the leak is significant, there is a chance that a section of the ceiling could collapse and this will cause significant damage. Often a ceiling has added layers, and with the weight of water, this can easily be 100kg or more from the water-saturated plasterboard ceiling. Even minor water stains should be treated with caution as modern paints and sealants can hold back significant water leaks.
Often the leak is minor, and the damage is hidden for some time; allowing it to spread across a larger area and causes mould and rot to start affecting the structure of the building.
While images of people holding saucepans are dramatic, they are rarely what happens in reality. Leaks are often slow and come from failed seals around the shower or other areas that need regular maintenance.