Question: Take All My Loves: 9 Shakespeare Sonnets is a studio album by Rufus Wainwright, features a guest appearance, by which Canadian-American folk-rock singer?
Context: Release the Stars is the fifth studio album by Canadian-American singer-songwriter Rufus Wainwright, released through Geffen Records on May 15, 2007.  Pet Shop Boys' Neil Tennant was the executive producer; the album was mixed by producers Marius de Vries and Andy Bradfield.  Wainwright's most commercially successful album to date, "Release the Stars" charted in 13 countries, reaching Top 10 positions in Denmark, Norway, and the United Kingdom, and was certified gold in Canada and the UK.  The album generated three singles: "Going to a Town", which peaked at number 54 on the UK Singles Chart, "Rules and Regulations", and "Tiergarten". Rufus Wainwright is the eponymous debut studio album by Canadian-American singer-songwriter Rufus Wainwright, released in the United States on May 19, 1998 through DreamWorks Records.  The album was produced by Jon Brion, with the exception of "In My Arms", which was produced and mixed by Pierre Marchand, and "Millbrook" and "Baby", which were produced by Brion and Van Dyke Parks.  Lenny Waronker was the album's executive producer. Rufus Does Judy at Carnegie Hall is the sixth album (and first live album) by the Canadian-American singer-songwriter Rufus Wainwright, released through Geffen Records in December 2007.  The album consists of live recordings from his sold-out June 14–15, 2006, tribute concerts at Carnegie Hall to the legendary American actress and singer Judy Garland.  Backed by a 36-piece orchestra conducted by Stephen Oremus, Wainwright recreated Garland's April 23, 1961, concert, often considered "the greatest night in show business history".  Garland's 1961 double album, "Judy at Carnegie Hall", a comeback performance with more than 25 American pop and jazz standards, was highly successful, initially spending 95 weeks on the "Billboard" charts and garnering five Grammy Awards (including Album of the Year, Best Album Cover, Best Solo Vocal Performance – Female and Best Engineering Contribution – Popular Recording). Vibrate: The Best of Rufus Wainwright, sometimes referred to simply as Vibrate: The Best Of, is the greatest hits album by American-Canadian singer-songwriter Rufus Wainwright, released on February 28, 2014 in Australia and Ireland by Universal Music Enterprises and in other nations subsequently.  The standard issue of the album includes eighteen songs from six of Wainwright's studio releases, including his self-titled debut album (1998), "Poses" (2001), "Want One" (2003), "Want Two" (2004), "Release the Stars" (2007) and "Out of the Game" (2012), plus soundtrack contributions and one previously unreleased track ("Me and Liza").  The deluxe version includes a bonus disc with sixteen rare and unreleased recordings, both live and studio recorded.  Featured are "Chic and Pointless", previously unreleased and produced by Guy Chambers, and "WWIII", a song that was co-written by Chambers and had not been released in a physical form until "Vibrate". Take All My Loves: 9 Shakespeare Sonnets is a studio album by Rufus Wainwright.  It features nine adaptations of Shakespeare's sonnets and guest appearances by Helena Bonham Carter, Fiora Cutler, Peter Eyre, Carrie Fisher, Inge Keller, Siân Phillips, Anna Prohaska, William Shatner, Martha Wainwright, and Florence Welch.  Released by Deutsche Grammophon and Universal Music Canada on April 22, 2016, the tribute album commemorates the 400th anniversary of William Shakespeare's death. Martha Wainwright (born May 8, 1976) is a Canadian-American folk-rock singer-songwriter.  She is the daughter of American folk singer and actor Loudon Wainwright III and Canadian folk singer-songwriter Kate McGarrigle.  She was raised in a musical family along with her older brother, Rufus Wainwright, in Montreal, Quebec, Canada. House of Rufus is a collection of six studio albums, two live albums (one being a double album), four additional albums of previously unreleased material, and six DVDs recorded by Canadian-American singer-songwriter Rufus Wainwright, reissued as a 19-disc box set in the United Kingdom on July 18, 2011.  Wainwright's official site claimed that the collection "spans Rufus' entire career and represents the most complete collection of Rufus Wainwright recordings to date." Rufus McGarrigle Wainwright (born July 22, 1973) is an American-Canadian singer, songwriter and composer.  He has recorded seven albums of original music and numerous tracks on compilations and film soundtracks.  He has also written a classical opera and set Shakespeare sonnets to music for a theater piece by Robert Wilson. All Days Are Nights: Songs for Lulu is the sixth studio album by Canadian-American singer-songwriter Rufus Wainwright, first released in Canada through Decca Records on March 23, 2010.  The album was produced by Wainwright (with Pierre Marchand on three tracks), and mixed by Marchand, who produced Wainwright's second album, "Poses" (2001). The discography of Rufus Wainwright, a Canadian-American singer-songwriter, consists of seven studio albums, three live albums, three compilations, three extended plays (EPs), three video albums, nine singles, and nine music videos. Wainwright's self-titled debut album was released through DreamWorks Records in May 1998.  Although his success was limited, Wainwright reached #24 on "Billboard's" Top Heatseekers chart, and "Rolling Stone" named him 1998's Best New Artist.  Wainwright's second album, "Poses", was released through the same label in June 2001, resulting in the #1 position on the Heatseekers Chart and #117 on the "Billboard" 200.  With material recorded from the same session, "Want One" was released through DreamWorks in September 2003, and "Want Two" was released through Geffen Records in November 2004.
Answer: Martha Wainwright