I saw the Prophet ﷺ, and Hasan bin Ali resembled him.
حدثنا محمد بن بشار حدثنا يحيى بن سعيد عن إسمعيل بن أبي خالد
رأيت النبي ﷺ وكان الحسن بن علي يشبهه
[Its isnad is sahih]. Nasai also narrated it in Al-Kubra, no. 8162, through Yahya Qattan, with the same wording. On this topic there is also a report from Jabir [Bukhari, no. 2296, 4383, and Muslim, no. 2314].