The guy next to Jack is Lou Adler. He's won two Grammy Awards in '72 in the Record of the Year category for producing "It's Too Late" and in the Album of the Year category for "Tapestry". Lou Adler is the owner of The Roxy Theatre in West Hollywood, California. Adler is best friends with actor Jack Nicholson and can often be found at his side at L.A. Lakers Basketball games.
You can find out more on Adler's career on IMDB: http://www.imdb.com/name/nm0004693/bio