After 20 seasons “American Idol” (ABC, 8 p.m.) should have at least 20 stars to boast but the stars they boast on today’s special episode are limited to Ruben Studdard, Scotty McCreery, Jordin Sparks, David Cook, Lauren Alaina, Kris Allen and a few names that don’t quite ring a bell.
The animated children’s series “Octonauts: Above & Beyond” (Netflix, streaming) returns for a second season.
Live semifinals continue for the “American Song Contest” (NBC, 8 p.m.).
On “9-1-1” (Fox, 8 p.m.), the term May Day means emergency.
Calvin and Tina offer to throw a quinceañera for a teen he’s mentoring at the shop on “The Neighborhood” (CBS, 8 p.m.).
The early years of the queen are explored in the new series “Elizabeth” (Smithsonian, 8 p.m.).
On “Bob Hearts Abishola” (CBS, 8:30 p.m.), Douglas is ready to introduce Olivia to his family.
Owen travels to Los Angeles for some personal business on “9-1-1: Lone Star” (Fox, 9 p.m.).
“NCIS: Hawai’i” (CBS, 10 p.m.) looks into the murder of a seaman during off hours.
Theo E.J. Wilson imagines himself at the Oklahoma City bombing on “I Was There” (History, 10 p.m.).
“The Endgame” (NBC, 10 p.m.) finally has its own end, at the end of the first season.
A documentary film crew inserts itself into the upcoming wedding day of “The Good Doctor” (ABC, 10 p.m.).
On “All American” (CW, 8 p.m.) things between Spencer and Olivia are shaky.
Simone has some ideas for her service week project on “All American: Homecoming” (CW, 9 p.m.).
“Spring Baking Championship” (Food, 8 p.m.) crowns a winner.
Jack the Ripper is the subject of “History’s Greatest Mysteries” (History, 9 p.m.).
“Black Ink Crew Compton” (VH1, 9 p.m.) has a party at the shop.
Busby Berkeley gets a Monday night showcase all month on Turner Classic Movies, starting with early successes in 1933 and 1934 “42nd Street” (8 p.m.), “Gold Diggers of 1933” (9:45 p.m.), “Footlight Parade” (11:30 p.m.), “Dames” (1:30 a.m.) and “Fashions of 1934” (3:15 a.m.).
Earlier the birthday of Theodore Bikel, born this day in 1924 is marked with “The Vintage” (8:30 a.m.). But mostly they jump the gun by noting the birthday of Bing Crosby, born May 3, 1903, with “Angels in the Outfield” (10:15 a.m.), “Road to Bali” (12:15 p.m.), “High Society” (2 p.m.), “Man on Fire” (4 p.m.) and “Robin and the 7 Hoods” (5:45 p.m.).
NBA Playoffs have Philadelphia at Miami (TNT, 7:30 p.m.) and Dallas at Phoenix (TNT, 10 p.m.).
Daytime Talk
Kelly Ripa and Ryan Seacrest: Jenna Dewan. The View: Jonathan Martin, Alexander Burns. The Talk: Kate Bosworth. Ellen DeGeneres: Serena Williams, Jay Shetty, Indigo Girls. Drew Barrymore: Donny Osmond, Marie Osmond, David Sedaris, Amy Sedaris, Clint Howard, Ron Howard. Kelly Clarkson: Lily Tomlin, Jane Fonda, Sasheer Zamata. Tamron Hall: Dave Coulier, Gabrielle Bernstein. Wendy Williams: Nicole Remy, Michael Rapaport. The Real: John Salley, Gabrielle Dennis.
Late Talk
Stephen Colbert: Jon Bernthal, Alton Brown. Jimmy Kimmel: Tom Cruise, Iliza Shlesinger, Parquet Courts. Jimmy Fallon: Norman Reed’s, Paula Pell, Beeple, the Linda Lindas. Seth Meyers: Laura Linney, Melanie Lynsey, Geoffrey Zakarian, Kristina Schiano. James Corden: Dakota Fanning, Jamie Bell, T-Pain.