Is it possible to have label in QGis 2.8 two different colours? For example Field1 in red colour and Field2 in blue (Field1 || ‘ ’ || Field2).
Yes, you need to duplicate the layer (right click on layer, and choose duplicate) for having different labels styles on the same layer. You may have to play with the label placement (Labels > Placement tab) for the alignment to fit.
Note when duplicating, what appears to be two layers is actually the same layer in the layer control / TOC. If you make a change to one layer the other layer will be updated when you press Save Layer Edits or toggles the editing tool.