The singer, who has supported the Rams since he was four, was being filmed at Pride Park for a new film being made about the boy-band.
The film is being directed by Morgan Spurlock, who is the documentary maker behind Supersize Me, where he ate nothing but fast food for 30 days to see what effect it had on his health.
Niall had a kick-about on the pitch with some of his friends before the game kicked off, but no other members of the group were there.
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A report is being released today, which includes a series of recommendations at reducing child poverty in Birmingham.
Bright or sunny spells across the region, especially in the morning but occasional showers are likely to develop in the afternoon.
A drier and brighter start to the day, but turning fairly cloudy by afternoon with showers or outbreaks of rain.