I had tried a prompt before the in-painting feature (image 2) but it didn't really work. In-painting (iamge 1) easily fixed that.
Image 1: image 2 + region vary: 'portrait of Batman'
Image 2: Batman::1.125 Star Trek Captain::
Image 1: image 2 + region vary: 'portrait of Batman'
Image 2: Batman::1.125 Star Trek Captain::