Question: What singer know as Mama Cass has a song in the opening credits of The Good Times Are Comin?

Context paragraphs:
Bubblegum, Lemonade, and... Something for Mama: Bubblegum, Lemonade and… Something for Mama is the second solo album released by Cass Elliot under the billing "Mama Cass".  It was recorded in 1969 and arranged and produced by Steve Barri.  The album was originally released on July 5, 1969, with only 11 tracks.  It was released again on December 6, 1969, under a new title and with a different album cover as Make Your Own Kind of Music/It’s Getting Better. " Make Your Own Kind of Music" had just become a hit and was added to the album.

Walt Conley: Walter Bell Conley (May 20, 1929 – November 16, 2003) was an American folk singer, Hollywood actor, voice actor, and owner of Denver’s folk venue Conley’s Nostalgia.  The Rocky Mountain News described Conley as the founding father of Denver's folk scene, which began in the late 1950s and stretched into the mid 1960s.  Conley shared stages with, and opened for, Josh White, Cisco Houston, Mama Cass Elliot, Floyd Red Crow Westerman, and Judy Collins among many others.  Conley also opened his home to a young and unknown Bob Dylan in the summer of 1960, and introduced Denver to the little known Smothers Brothers that same year.  As the owner of Conley’s Nostalgia, Walt brought in big name performers such as John Fahey and Dave Van Ronk.  To those who worked with him, knew him, and wrote about him, he is referred to as Denver’s “Grandfather of Folk Music.”  Conley remained an entertainer until he died from a massive stroke at the age of 74.  At the time of his death Conley was married to Joan Holden.  Conley had four children from previous relationships.  Conley's resting place is the Fort Logan National Cemetery in Denver, Colorado.

Doctors' Wives (1971 film): Doctors' Wives is a 1971 American drama film directed by George Schaefer and starring Dyan Cannon, Gene Hackman, Carroll O'Connor, Richard Crenna, Janice Rule, John Colicos, and Rachel Roberts.  It was based on a novel by Frank G. Slaughter.  The theme song, "The Costume Ball", was sung by Mama Cass Elliot.

It's Getting Better: It's Getting Better is a song written by Barry Mann and Cynthia Weil that was a sunshine pop hit single in 1969 for Mama Cass.

Monte Walsh (1970 film): Monte Walsh is a 1970 film directed by cinematographer William A. Fraker.  His directorial debut, it stars Lee Marvin, Jeanne Moreau and Jack Palance.  The name "Monte Walsh" is taken from the title of a 1963 western novel by Jack Schaefer, but the film has little to do with the plot of Schaefer's book.  The film was set in Harmony, Arizona.  A made-for-TV remake was set in Wyoming and directed by Simon Wincer, with Tom Selleck and Isabella Rossellini playing the parts of Monte and Martine.  The story has elements of a tragedy.  The song played over the opening credits is "The Good Times Are Comin' " by Mama Cass, with music and lyrics by John Barry and Hal David.

I Know There's Gonna Be (Good Times): "I Know There's Gonna Be (Good Times)" is a song by English music producer Jamie xx, with featured vocals from American rapper Young Thug and Jamaican musician Popcaan.  The song was released as the third single from Jamie xx's debut studio album, "In Colour", on 22 May 2015 in the UK and 28 August in the U.S.  The official music video for the song was uploaded to YouTube on 28 September 2015.  "I Know There's Gonna Be (Good Times)" peaked at number 115 on the UK Singles Chart and number 90 on the Australian ARIA Charts.  It also appears on the soundtrack for the video game "NBA Live 16" and "NBA 2K17".  English rapper Skepta's grime-influenced remix of the song made its debut on Drake's "OVO Sound Radio" on Apple Music's Beats 1 radio station.

Gary Burden: Gary Burden is an American artist specializing in the field of album covers.  He is considered as one of the pioneers of the concept of album cover art.  In the 1960s and 1970s he designed covers for many rock stars, such as Mama Cass, Crosby Stills Nash and Young, Joni Mitchell, The Doors, The Eagles and Jackson Browne.  He created album covers for Neil Young for 35 years.  His works were nominated four times for the Grammy Awards.  and in 2010, he won the 52nd Grammy Awards for Best Boxed or Special Limited Edition Packaging for the Neil Young "The Archives Vol.  1 1963–1972".  The titles of creative director, art director and designer are mutually shared amongst Gary Burden, Jenice Heo and Neil Young who collaborated throughout the design process.

Cass Elliot: Cass Elliot (born Ellen Naomi Cohen; September 19, 1941 – July 29, 1974), also known as Mama Cass, was an American singer and actress, best known as a member of the Mamas & the Papas.  After the group broke up, she released five solo albums.  In 1998, Elliot, John Phillips, Denny Doherty, and Michelle Phillips were inducted into the Rock and Roll Hall of Fame for their work as the Mamas & the Papas.

Mama's Big Ones: Mama’s Big Ones is the third solo album released by Mama Cass.  It was also the last studio album she released for Dunhill in order to fulfill her three album deal.

Dream a Little Dream (Cass Elliot album): Dream a Little Dream is the debut solo album by singer Mama Cass immediately after the breakup of The Mamas & the Papas, though she was still billed as "Mama Cass" for this release.  Capitalizing on the success of her first solo song as the album's title, it was released on October 19, 1968 by Dunhill Records.  The album was re-released by MCA Japan in 2001.

Supporting paragraphs: Monte Walsh (1970 film) Cass Elliot
Answer: Cass Elliot