Fetching Merge Request's branch from a private fork

Merge Request from a Private Fork

I have a public repository and someone created a private fork of it. They opened a merge request from their private fork and I can see the code and commits in the GitLab UI. But how can I fetch their code as a branch into my clone of my repository??

GitHub, for instance, will make commits from any Merge Requests from fork available on the target repository to be fetched either by SHA or you can use a special ref to fetch commits from a Merge Request.

Does GitLab have something similar or how else can we access commits in a Merge Request from a private fork?