Dec 12 (Reuters) - Veteran television journalist Chris Wallace announced on Sunday that he is leaving Fox News after about 18 years and he is set to join rival CNN"s upcoming streaming service as an anchor. Wallace, 74, hosted the program "Fox News Sunday," and announced his departure on the show. He was one of the most prominent journalists at Fox News, including moderating a presidential debate last year between Republican Donald Trump and Democrat Joe Biden. "I want to try something new, to go beyond politics to all the things I"m interested in. I"m ready for a new adventure," Wallace said. CNN said Wallace will join the company as an anchor for its streaming service CNN+, which will debut early next year. "I am thrilled to join CNN+. After decades in broadcast and cable news, I am excited to explore the world of streaming," Wallace said in a CNN statement, adding that he also looks forward to the "new freedom and flexibility streaming affords." In a statement, Fox News said other journalists from the network will host "Fox News Sunday" until a replacement is named. During last year"s presidential debate, Wallace sought to stop Trump"s interruptions, asking the then-president at one point: "Why don"t you observe what your campaign agreed to as a ground rule. Okay, sir?" Trump at another point objected to a Wallace question on healthcare policy, saying, "I guess I"m debating you not him (Biden). But that"s okay. I"m not surprised." Wallace is the son of the late broadcast journalist Mike Wallace.