and his son Parker Aiken
, 9 months, visit an office building on Wednesday (May 13) in Beverly Hills, Calif.
The 30-year-old former American Idol
contestant will be making his cameo on 30 Rock
's season finale, where Jack (Alec Baldwin
) builds a relationship with his estranged father. The episode ("Kidney Now!") airs TOMORROW, May 14 @ 9:30PM ET/PT on NBC. Also making guest-starring appearances: