Cannot add 'Modified Time' to page layout

Cannot add 'Modified Time' to page layout

I have created a section where I want to show details about when a Lead was last edited and by whom. However, I cannot find the 'Modified Time' field anywhere in the page layout customization screen. Although I can see the 'Modified By' field.
Does anyone know from where I can add this field to the page layout?

Thanks,

Soubhik