First recorded by Albert Clough (US #2 1911).
Other popular versions by The Peerless Quartet (US #1 1911), Oliver Hardy & Stan Laurel (1938), Mitch Miller (1961), Timi Yuro (MOR #15 1962).
Also recorded by Bing Crosby (1934).
From the wiki: “‘Let Me Call You Sweetheart’ was written by Leo Friedman with lyrics by Beth Slater Whitson. The song was published in 1910 and first recorded by Albert Clough in May, 1911. The Peerless Quartet recorded their version in November, 1911, topping the sheet music chart that year. The song was also comically sung by Oliver Hardy (with Stan Laurel playing the tuba) in the 1938 motion picture Swiss Miss.”