Jenkins first came to public attention when she sang at Westminster Cathedral honouring Pope John Paul II's silver jubilee in October 2003 and then supporting Aled Jones on tour.
At the Rugby World Cup in 2003 she made her Sydney Opera House debut as a guest of fellow Welshman, Max Boyce and, in August 2004, her first USA appearance, supporting Hayley Westenra at Joe's Pub in New York City.

Jenkins was the first person to perform the Home Nations anthem "The Power of Four" and began to appear regularly to sing the Welsh national anthem "Hen Wlad Fy Nhadau" at Welsh international rugby union matches, singing with Bryn Terfel at the 2005 Wales vs. England Six Nations match at the Millennium Stadium.
In 2005, she became the official mascot for the Wales rugby union team.

On 22 January 2005, Jenkins sang in Cardiff at the Tsunami Relief Concert and in April and May of that year supported Irish tenor Ronan Tynan on his first US tour as a solo artist.
That May she sang at Trafalgar Square to a 15,000-strong audience celebrating the 60th Anniversary of VE Day.
At the Berlin stage of Live 8 in 2005, Jenkins sang the hymn "Amazing Grace", and she later helped to launch The Royal British Legion's poppy appeal at Covent Garden whilst wearing a dress made of 2,500 poppies.

On 27 August 2005, Jenkins performed "Abide With Me" at the Rugby League Challenge Cup Final at the Millennium Stadium in Cardiff which was attended by 74,213 spectators.
During the anthem, BBC cameras captured the moment of a Hull F.C. fan being brought to tears during the song.
 
With the Blue Man Group, Jenkins sang "I Feel Love" in front of the Queen at the Royal Variety Performance on 21 November 2005.
She performed at the Nobel Peace Prize Concert in Oslo, Norway, on 11 December 2005.

In November 2006 she performed before the Queen at the Royal British Legion Festival of Remembrance at the Royal Albert Hall and joined fellow Welsh singer James Fox in the final verse of "Anthem" from the musical Chess.

In July 2007, Jenkins gave a concert at Margam Park in south Wales, performing alongside Paul Potts and Juan Diego Flórez.
Jenkins extended a personal invitation to Potts to sing "Nessun dorma" at the concert.

In September 2007, Jenkins modeled at Naomi Campbell's Fashion Relief event for charity in a Julien Macdonald dress which was then bought by Sir Philip Green for £10,000.

In November 2007 she sang again at the Royal British Legion Festival of Remembrance at the Royal Albert Hall and was named classical performer of the year at the Variety Club Showbiz Awards.

With Darcey Bussell she has appeared in a stage song-and-dance production, entitled Viva la Diva, paying tribute to stars including Madonna and the late Judy Garland (who died in 1969).
The show opened in Manchester in November 2007.
Jenkins learned to tap dance, spending eight hours a week learning the choreography and running three miles a day to get fit.
She performed the Welsh National Anthem on 17 May 2008 at the 2008 FA Cup Final between Cardiff City and Portsmouth, becoming the first person to do this at an FA Cup Final.

At the beginning of 2009, Jenkins performed in South Korea with Plácido Domingo.
This was Jenkins's third concert with Domingo having performed with him in Hong Kong in 2008 and Athens in 2007.
They then performed together in May 2009 at The Classical Brit Awards.

On 8 July 2009, Jenkins performed at the opening ceremony of the Ashes Test Series at Sophia Gardens cricket ground in Cardiff.
On 12 September 2009, she performed in Hyde Park for Proms in the Park.

On 21 September 2009, she performed at the memorial service for Sir Bobby Robson, singing "Pie Jesu" at the request of Lady Robson.
O n 12 November 2009, Jenkins performed a duet with cellist Julian Lloyd Webber for Children in Need at the Royal Albert Hall.
The same month, Jenkins performed "I Believe" (from Believe) with Andrea Bocelli on his PBS Christmas Special.
The duet appears in his album, My Christmas.
Jenkins was scheduled to do her first Arena tour in March 2010.

On 24 May 2010, as part of the Argentina Bicente
Jenkins first came to public attention when she sang at Westminster Cathedral honouring Pope John Paul II's silver jubilee in October 2003 and then supporting Aled Jones on tour. At the Rugby World Cup in 2003 she made her Sydney Opera House debut as a guest of fellow Welshman, Max Boyce and, in August 2004, her first USA appearance, supporting Hayley Westenra at Joe's Pub in New York City.
Jenkins was the first person to perform the Home Nations anthem "The Power of Four" and began to appear regularly to sing the Welsh national anthem "Hen Wlad Fy Nhadau" at Welsh international rugby union matches, singing with Bryn Terfel at the 2005 Wales vs. England Six Nations match at the Millennium Stadium. In 2005, she became the official mascot for the Wales rugby union team.
On 22 January 2005, Jenkins sang in Cardiff at the Tsunami Relief Concert and in April and May of that year supported Irish tenor Ronan Tynan on his first US tour as a solo artist. That May she sang at Trafalgar Square to a 15,000-strong audience celebrating the 60th Anniversary of VE Day. At the Berlin stage of Live 8 in 2005, Jenkins sang the hymn "Amazing Grace", and she later helped to launch The Royal British Legion's poppy appeal at Covent Garden whilst wearing a dress made of 2,500 poppies.
On 27 August 2005, Jenkins performed "Abide With Me" at the Rugby League Challenge Cup Final at the Millennium Stadium in Cardiff which was attended by 74,213 spectators. During the anthem, BBC cameras captured the moment of a Hull F.C. fan being brought to tears during the song.  
With the Blue Man Group, Jenkins sang "I Feel Love" in front of the Queen at the Royal Variety Performance on 21 November 2005. She performed at the Nobel Peace Prize Concert in Oslo, Norway, on 11 December 2005.
In November 2006 she performed before the Queen at the Royal British Legion Festival of Remembrance at the Royal Albert Hall and joined fellow Welsh singer James Fox in the final verse of "Anthem" from the musical Chess.
In July 2007, Jenkins gave a concert at Margam Park in south Wales, performing alongside Paul Potts and Juan Diego Flórez. Jenkins extended a personal invitation to Potts to sing "Nessun dorma" at the concert.
In September 2007, Jenkins modeled at Naomi Campbell's Fashion Relief event for charity in a Julien Macdonald dress which was then bought by Sir Philip Green for £10,000.
In November 2007 she sang again at the Royal British Legion Festival of Remembrance at the Royal Albert Hall and was named classical performer of the year at the Variety Club Showbiz Awards.
With Darcey Bussell she has appeared in a stage song-and-dance production, entitled Viva la Diva, paying tribute to stars including Madonna and the late Judy Garland (who died in 1969). The show opened in Manchester in November 2007. Jenkins learned to tap dance, spending eight hours a week learning the choreography and running three miles a day to get fit. She performed the Welsh National Anthem on 17 May 2008 at the 2008 FA Cup Final between Cardiff City and Portsmouth, becoming the first person to do this at an FA Cup Final.
At the beginning of 2009, Jenkins performed in South Korea with Plácido Domingo. This was Jenkins's third concert with Domingo having performed with him in Hong Kong in 2008 and Athens in 2007. They then performed together in May 2009 at The Classical Brit Awards.
On 8 July 2009, Jenkins performed at the opening ceremony of the Ashes Test Series at Sophia Gardens cricket ground in Cardiff. On 12 September 2009, she performed in Hyde Park for Proms in the Park.
On 21 September 2009, she performed at the memorial service for Sir Bobby Robson, singing "Pie Jesu" at the request of Lady Robson.O n 12 November 2009, Jenkins performed a duet with cellist Julian Lloyd Webber for Children in Need at the Royal Albert Hall. The same month, Jenkins performed "I Believe" (from Believe) with Andrea Bocelli on his PBS Christmas Special. The duet appears in his album, My Christmas. Jenkins was scheduled to do her first Arena tour in March 2010.
On 24 May 2010, as part of the Argentina Bicente
Katherine Jenkins