In preparation for his Jazz Fest appearance, Jeff Beck (Apr. 29, 3:20 p.m., Acura Stage) will perform on American Idol this Wednesday, April 6. He’ll perform a song with the remaining contestants, each song by a Rock and Roll Hall of Fame inductee. Could we see Beck accompany Pia Toscano on “I Walk on Gilded Splinters” or Paul McDonald on “Tom Traubert’s Blues”? Dare to dream.