The masked lion, specifically known as 'Sir Lion', is Billy Bush.
Based on the provided video reference titled "Billy Bush becomes 'Sir Lion' on The Masked Singer", the identity of the character referred to as the "masked lion" is Billy Bush. The video title directly links Billy Bush to the 'Sir Lion' persona, which is a masked character appearing on the show The Masked Singer.
The excerpt from the video transcript includes someone stating, "Me. And they snuck it and they sent it over to Fox. And said please get this clown off of our hands... so I went over." This indicates participation in a show or project, aligning with the context of being a contestant or participant on The Masked Singer as suggested by the video title.
Therefore, the masked lion, identified as 'Sir Lion' in the context of The Masked Singer, is Billy Bush.
