Dublin Bus has confirmed that is investigating footage of a person hanging onto the back of a fast-moving bus.
The footage was shared on social media this week.
It is believed to have been taken as the bus was driving through Finglas this week.
In a statement, Dublin Bus warned that the action shown in the footage is unsafe and extremely dangerous.
The company said it strongly discourages anyone from partaking in such reckless behaviour that could result in serious injury.