Xu Zhengxi (Chinese: 徐正溪, born May 5, 1985), also known as Jeremy Tsui, Izz Xu, Jones Xu, or Jeremy Jones Xu, is a Chinese actor. He gained great popularity for his role as Yuwen Hu in the historical drama "The Legend of Dugu," as well as for his role as the antagonist in the costume drama "Siege in Fog."

He speaks Mandarin, Cantonese, and English. Before achieving success, he suffered from hyperthyroidism but recovered.

On March 15, 2024, he announced his retirement from acting on his personal Weibo account. On September 14, 2024, both he and his agency posted statements on Weibo explaining that his decision was prompted by the worsening health of his father, which forced him, as an only child, to deal with the situation, adding that a satisfactory solution had by then been found allowing him to return to acting.