Alex Donnelley is a German-born American actress. Her best known role is that of Diane Jenkins on the CBS soap opera The Young and the Restless from 1982 to 1984, and again in 1986. Donnelley went on to reprise her role again from October 1996 to February 2001. She may also be known for her minor role in Cruel Intentions 3. Donnelley has two daughters from her former marriage to musician Robert Lamm. In 2010, Donnelley briefly dated singer Billy Joel.