Answer by taking a quote from the following article:

Gary Barlow OBE (born 20 January 1971) is an English singer, songwriter and record producer. He is best known as the lead singer of the British pop group Take That. Barlow also served as head judge of The X Factor UK in 2011, 2012 and 2013 and Let It Shine in 2017. Barlow is one of Britain's most successful songwriters, having written fourteen number one singles and twenty-four top 10 hits.

After leaving his career as a solo artist Barlow returned to his first love of writing music. He soon signed a song writing publishing deal with Sony and went to the US on a six-month songwriting project, residing in Nashville, Los Angeles and New York with his wife, Dawn and first child, Daniel. Upon his return he set up True North Productions with Eliot Kennedy and Tim Woodcock. In his autobiography 'My Take' Barlow partly blames his fall as a solo artist on his commitments to being a star in the United States. After his disappointing second album, Barlow remained out of the public eye for half a decade, choosing to continue to write and produce songs for other artists such as Shirley Bassey and Charlotte Church In October 2007, Barlow founded San Remo Live Publishings as an independently run management company to establish and support artists and songwriters.  In 2010 Barlow signed a new 5-year song writing publishing deal with Sony music. He has been voted as the greatest British songwriter of all time in a 2009 OnePoll, who surveyed 3,000 people John Lennon and Paul McCartney, of The Beatles, were placed second and third respectively.  In 2011, Barlow wrote the song "Run for Your Life" for The X Factor series 7 winner Matt Cardle's debut album. Cardle told The Sun: "We had 99% of the album finished then the track came through from Gary. I'd been trying to write a song like that for a long, long time, probably five or six years. As soon as I heard it I just felt the song was mine. Lyrically it's about not being good enough for the person you're with. I was nearly in tears recording the vocals. I'm proud that I've written a lot of the album but Gary is a genius as a writer - I couldn't pass it up." He has also written for the likes of Robbie Williams, Westlife, Lily Allen, Blue, Elton John, Olly Murs Matt Cardle, T-Pain, Will Young N-Dubz, Lawson, Shirley Bassey, Donny Osmond, Delta Goodrem, Elaine Paige, Agnetha Faltskog and many more while also being commissioned by the Queen to write the official single for her Diamond Jubilee which saw Barlow collaborate with Andrew Lloyd Webber.  To date Barlow has written 14 number 1 singles in the UK, and 2 Billboard Hot 100 top 10 singles in the United States including Back for Good which went to number 1 in 31 countries across the world.

What is another artist that Gary worked with?
He has also written for the likes of Robbie Williams, Westlife, Lily Allen, Blue, Elton John,