After watching The Undiscovered Country I noticed that the advocate for Kirk and Bones during their trial is none other than Michael Dorn, a.k.a. Worf. During the trial I believe they even call the advocate Worf by name.
How can this be when Worf is alive and aboard the Enterprise D almost 70 years later? Is there any in-universe explanation for this, or any outside universe explanation for why Michael Dorn is in Undiscovered Country?