Is there a way to change email id for already commited stuff on github?

I have been using GitHub and Bitbucket for different repositories. For my Github repo, I realized later that I have been using bitbucket email to commit and push on to Github. I am not sure if it is possible to change those already pushed commits to my email? I already changed email back on GitHub to make sure my future commits and pushes go from the email I want. Oh I also connected Bitbucket to my GitHub.