How do I Look for text within a string and wrap it in BBcode?

Hi there, have tried searching for this but the answer escapes me.

What I'm looking to do is search in a string of text for specific words or phrases and wrap those words/phrases in bbcode to change the colour of them.

For example, the string would be

"Hello there, you'll need to speak to Martha about that!"

I'd like to search for the word Martha, and wrap it in BBcode so it returns

"Hello there, you'll need to speak to [color=#ff0000]Martha[/color] about that!"

Is this possible? Thanks so much!

You can use replace() expression.

Set text to replace(string, "Martha", "[color=#ff0000]Martha[/color]")