Watch clips from Alexander's appearance below:
Jason Alexander Re-Records Costanza's Message for Kat Dennings
"After learning Kat Dennings' voicemail has been the famous George Costanza answering machine song, Jason records a custom version for the '2 Broke Girls' star."
Jason Alexander Relentlessly Pursued His Wife
"Jason tells James about his courtship with his wife, whom he's been married to for 33 years, and how he finally got her to accept his marriage proposal."
Alexander, who won the 1989 Tony as Outstanding Actor in a Musical for Jerome Robbins' Broadway, made his Broadway debut in the original cast of Stephen Sondheim and George Furth's 1981 Merrily We Roll Along, and made his last Broadway appearance in 1990's Accomplice.