How do I achieve formatting of a text inside a TextBlock control in my WPF application?

e.g.: I would like to have certain words in bold, others in italic, and some in different colors, like this example:

enter image description here

The reason behind my question is this actual problem:

lblcolorfrom.Content = "Colour From: " + colourChange.ElementAt(3).Value.ToUpper();

I would like the second part of the string to be bold, and I know that I could use two controls (Labels, TextBlocks, etc.) but I'd rather not, due the vast amount of controls already in use.

c# wpf wpf-controls
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