Police have arrested an individual as part of their investigation into the incident in which a coin was thrown at West Brom midfielder Chris Brunt.

The Northern Ireland international was hit by a coin thrown from among the visiting supporters as Tony Pulis's side was beaten 3-1 away to Reading in the FA Cup fifth round on Sunday (AEDT).

Brunt, who had gone to hand his shirt to a child in the crowd, said he was "disgusted" and "ashamed" by the incident and West Brom assured it would issue a lifetime ban to the culprit.

Thames Valley Police (TVP) opened an investigation into the incident and stated on Wednesday (AEDT) that they had made an arrest.

"TVP and Hampshire Police made an arrest today in relation to a coin throwing incident at the Reading vs West Brom FA Cup match on Saturday," a statement read.

A fan group plans to hold a collection for donations to a charity of Brunt's choice prior to their Premier League game with Crystal Palace on Saturday.