Kate Walsh played Dr. Addison Montgomery on Grey's Anatomy.
Stefan Zucker -LRB- born 1949 -RRB- is an American singer , expert on Italian opera and self-described `` opera fanatic . ''. American. United States. He was listed in the 1980 Guinness Book of Records as the `` world 's highest tenor '' for having hit and sustained an A above high C for 3.8 seconds at The Town Hall in New York City on September 12 , 1972 .. Guinness Book of Records. Guinness Book of Records. The Town Hall. The Town Hall