.htaccess redirection with chars manipulation

Is there an way I can use a regex to redirect (301) URLs int he .htacces in a way that domain.com/My_Name.html will be redirected to domain.com/my-name ? Need to replace all _ with -, lower case the chars and subtract the ".html"

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EDIT: I need to replace all _ chars, no matter how many of them are in the URL开发者_Python百科.

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RewriteEngine on
RewriteRule ^(\w+)_(\w+)\.html$ ${tolower:$1}-${tolower:$2}

Not yet tested, but I'm pretty sure this will work.