Setting field visibility in ArcMap using C#?

Question

I want to set certain fields of a featurelayer to be visible on startup. how would I go about changing the field visibility of certain fields?

if (featureLayer.Name == "LayerName")
{
 // Code to set certain fields to visible
}

I tried using the IFields

IFields fields = featClass.Fields;
IField field = null;
for (int i = 0; i < fields.FieldCount; i++)
{
 field = fields.get_Field(i);
 if (field.Name == "ObjectID")
 // field.Visible = false;
}

but I dont see a visibility property

UPDATE: Here is the equivalent code based on Hornbydd's answer below in C#

void SetFieldVis()
{
 // Get Document
 IMxDocument pMXD = ArcMap.Application.Document as IMxDocument;
 // Get Map
 IMap pMap = ArcMap.Document.FocusMap;
 // Get first layer in TOC -> in my case set up an enum and loop through the layers
 UIDClass uid = new UIDClass();
 uid.Value = "{40A9E885-5533-11d0-98BE-00805F7CED21}";
 IEnumLayer enumLayers = map.get_Layers(uid, true);
 IFeatureLayer pFeatureLayer = enumLayers.Next() as IFeatureLayer;
 while (pFeatureLayer != null)
 {
 if (pFeatureLayer.Name == "LayerName")
 {
 // Get a pointer to the fields
 ILayerFields pLayerFields = featureLayer as ILayerFields;
 // Get the fourth field by it's index number and set its visibility to False
 pLayerFields.FieldInfo[3].Visible = false;
 }
 }
}

Answer 1

Here is some VBA showing you how to change the visibility of a field for a layer loaded in ArcMap.

Public Sub SetFieldVis()
 ' Get Document
 Dim pMXD As IMxDocument
 Set pMXD = ThisDocument
 ' Get Map
 Dim pMap As IMap
 Set pMap = pMXD.FocusMap
 ' Get first layer in TOC
 Dim pFeatureLayer As IFeatureLayer
 Set pFeatureLayer = pMap.Layer(0)
 ' Get a pointer to the fields
 Dim pLayerFields As ILayerFields
 Set pLayerFields = pFeatureLayer
 ' Get the fourth field by it's index number and set its visibility to False
 Dim pFieldInfo As IFieldInfo3
 Set pFieldInfo = pLayerFields.FieldInfo(3)
 pFieldInfo.Visible = False
End Sub