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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Music fans face an anxious wait as tickets go on sale from 9am. The festival takes place at Weston Park in Staffordshire in August.
A conference looking at how use education to eradicate female genital mutilation is taking place in Leicester today.
Frost free tonight then mainly dry and bright tomorrow.