Question: Jean Terrell and Forrest Kline, have which mutual occupation?

Context paragraphs:
Hellogoodbye: Hellogoodbye (sometimes styled as hellogoodbye) is a pop rock band that was formed in Huntington Beach, California in 2001 by singer Forrest Kline.  They were signed to Drive-Thru Records and released their first full-length album "Zombies!  Aliens!  Vampires!  Dinosaurs! " in 2006, in addition to their previously released EP "Hellogoodbye" and DVD "OMG HGB DVD ROTFL".  In 2010, the band released "Would It Kill You? " on their label Wasted Summer Records.  The album was released in the United Kingdom and Europe by LAB Records on the 14 March 2011.  Hellogoodbye released their third album, Everything is Debatable, on October 29, 2013, while touring as the opening act for Paramore's The Self-Titled Tour.

Ernie Terrell: Ernest "Ernie" Terrell (April 4, 1939 – December 16, 2014) was an American professional boxer who competed from 1957 to 1973.  He held the WBA heavyweight title from 1965 to 1967, and was one of the taller heavyweights of his era, at a height of 6 ft .  Terrell was the older brother of The Supremes' early 1970s lead singer Jean Terrell.  In the 1960s, Jean sang with his group Ernie Terrell & the Heavyweights.

Zombies! Aliens! Vampires! Dinosaurs!: Zombies!  Aliens!  Vampires!  Dinosaurs!  is the debut studio album by American indie pop band Hellogoodbye.  Produced by Matt Mahaffey, Jeff Turzo, and Forrest Kline, the album was released on August 8, 2006 in the United States by Drive-Thru Records.  The album's lead single, "Here (In Your Arms)", reached number 14 on the "Billboard" Hot 100 and was certified platinum in the United States.

I Had to Fall in Love: I Had to Fall in Love was the only solo album released by former Supremes lead singer Jean Terrell, released in 1978 on the A&M label.  The album was completed five years after she left the Supremes and when it was finished, promotion was stopped completely because of Terrell's strict religious beliefs that prevented her from promoting the album in a way that she did not favor.  In 2006, an independent label re-released the album in CD format.  The title track is also available on the Motown compilation CD "The Supremes: Greatest Hits and Rare classics, 70's".

Forrest Kline: Forrest Scott Kline (born November 7, 1983, in Ashland, Oregon) is an American musician, songwriter, lead singer, and guitarist.  He is a member of the power pop band Hellogoodbye.

Jean Terrell: Jean Terrell (born Velma Jean Terrell, November 26, 1944 in Belzoni, Mississippi) is an American R&B and jazz singer.  She replaced Diana Ross as the lead singer of The Supremes in January 1970.

You Gotta Have Love in Your Heart: "You Gotta Have Love in Your Heart" is a duet single between Motown singing groups The Supremes and the Four Tops, released as a single from their "The Return of the Magnificent 7" album in 1971.  The single became a modest charter peaking at #55 on the U.S. "Billboard" Hot 100 chart and #41 on the U.S. "Billboard" R&B Singles Chart.  The single fared better in the UK, where it reached #25 in the official top 50 single chart.  Lead vocals were by the groups' respective lead singers Jean Terrell and Levi Stubbs.

Hellogoodbye (EP): Hellogoodbye is the eponymous debut EP from Hellogoodbye.  It was released on August 17, 2004 by Drive-Thru Records.  All the vocals and instruments were recorded solely by Forrest Kline, except for the lead vocals on track 4, which were performed by Jesse Kurvink.

This Is the Story: The '70s Albums, Vol. 1 – 1970–1973: The Jean Terrell Years: This Is the Story: The '70s Albums, Vol.  1 – 1970–1973: The Jean Terrell Years

Would It Kill You?: Would It Kill You?  is the second studio album by Hellogoodbye.  It was released November 9, 2010.  "When We First Met" was the album's lead single, and it was released for free download on September 5, 2009.  The album was produced by Forrest Kline, the frontman for the group.

Supporting paragraphs: Jean Terrell Forrest Kline
Answer: singer