A funny story:
My husband is an identical twin. A couple of years ago, his brother had a bad stroke and could barely walk or speak. We came to visit, and were all masked up when we walked in. But my husband had taken off his mask at one point, and had forgotten to put it back on when he left the patient room to ask a question at the nursing station.
The nurses at that station did a double-take, and one looked genuinely shocked. She began to ask how he was able to do that, when I realized the source of their confusion and shock, and I loudly interjected, "They're identical twins. This is his brother."
The nurses joined my husband and I in a long laugh.
[At the time of his stroke, my brother-in-law did not have his beard and was about the same weight as my husband, which is why the nurses were confused. And yes, my BIL is doing much better now.]