Oh well, tried out of curiosity and it works:
Text in query is build this way:
Code:
combinedBackground: [Background] & Chr(13) & Chr(10) & "<font color=""blue"">" & [Background_Internal] & "</color>"
Also, text box on report must have Text Format property set to "Rich Text". And a little trick - you can't change that property unless you save record source for report as static query (not SQL).
(Static query? Is that a proper name for it? Sorry, but English is not my first language...).
Edit: Small change, I realized after posted screenshot. Apparently there's no need for closing tags and it works better without it. Also chr(10) & chr(13) have no effect at all, better to use html <br> tag.
Code:
combinedBackground: [Background] & "<br><font color=""blue"">" & [Background_Internal]