After completing the diploma Gareth was accepted on the 3 year Musical Theatre Course at The Arts Educational Schools in Chiswick, London where he trained for three years. At college his roles included J.B.Biggley in How to Succeed in Business Without Really Trying, Papa Ga in Once On This Island, Major Holmes in The Secret Garden and created the role of Coaster in The World Premiere of 'Club Tropicana' and understudied Sonny and Blue Juice.

Near the end of Gareths third year at Artsed, he was snapped up by Franco Zeffirelli to play the role of Cicciolina in Pagliacci at The Royal Opera House in London, so left drama school earlier than expected. Later that year he filmed the UKG2 boyband launch commercial.

In 2004 he returned to The Royal Opera House to be an Assistant Dance Captain and to play the role of a Policeman in 'Lady Macbeth of Mtsensk', which went on to win an Olivier Award for Best Opera.

In December of that year, Gareth was approached again by Franco Zeffirelli to reprise the part of Cicciolina at The Israeli Opera House.

After returning from Israel in February 2005, he landed the role of Russell Tate in Waking The Dead - Series 5.

Gareth then landed the role of Gavin James in 'Mike Bassett TV' a spin off series of the 2001 film of the same name. The series starred Ricky Tomlinson and Amanda Redman who reprised their roles from the film. The show was aired on ITV in September 2005.

In the Summer of 2005 Gareth returned to the stage to perform as Snout in 'A Midsummer Nights Dream' and Pedant in 'Taming of the Shrew', both for 'The British Shakespeare Company'. Days after the Shakespeare festival, Gareth flew out to reprise his role of Cicciolina for the third year running, this time in Athens, Greece.

In 2006, Gareth ventured into the world of pop and filmed the Pet Shop Boys promotional video for their top ten smash, 'I'm With Stupid'. Although you do not see much of Gareth in the video, he was used as Matt Lucas' body double, and had to have a bald cap put on (on some of the shots, if you look careful enough, you can see that it is Gareth!)

On the Philip Schofield hosted ITV series 'Its Now Or Never', Gareth performed as both a dancer and vocalist for both episodes of the show. He then went on to film the Sainsburys Taste the Difference television advertisement campaign with Jamie Oliver and this was followed up by another role with Jamie for his School Dinner idents for Channel 4!

In 2007 Gareth was approached by Disney and asked to play the role of Corbin in a new 5 minute long promo for High School Musical.

Gareth’s foray into the commercial market proved even more successful when he landed a role in the new Pot Noodle adverts released in August that year playing a singing welsh miner, and straight after filmed the promos for Fist of Zen on MTV.

Gareth flew to Israel in late 2007 to rehearse Pagliacci which then went on to a winning run as the tour was extended to Moscow to perform the show. This was his 4th reprise in Franco Zeffirellis production of 'Pagliacci'.

Gareth returned to his base in London to film the TV Pilot 'Band Edge'. Gareth not only played the part of Phat Boy, but was also Associate Producer on the Show.

In 2008 Gareth filmed the following adverts: 'Quattro' Wilkinson Sword advert, Carlsberg 'Goal Celebration' advert, the Dancing Face of 'Visa' online, the running man in Channel 4's 'Next Generation' advert, before flying to Norway to play a Sumo Wrestler in the 'PRIX Supermarket' commercial.

In 2009, Gareth started the year filming 'Bev Allen - Life Coach' a new TV Pilot and on the first day of filming became an Uncle to Joseph Mason!!!!! Gareth then went on to perform as Ciccolina for a fifth and sixth time as Pagliacci was staged in Florence and Rome in Italy.

Gareths additional performances in 2009 included starring on 'The Graham Norton Show' performing a dance to the James Bond Theme, playing 'Shoe Boy' and a featured dancer in 'We Are Klang' for BBC 3. Gareth then went to Cyprus to play a special and well received run as Bustopher Jones and Gus in 'CATS - The Musical'.

During 2010 Gareth completed a SKY commercial, filmed his hilarious spoof of Cheryl Coles 'Fight For This Love' which has now had over a Million hits worldwide and was shown on 'Live from Studio Five'. He also filmed an episode of 'The Armstrong & Miller Show' and appeared as Vernon Kays comedy Assistant on 'All Star Family Fortunes' for ITV.

In early 2011 Gareth was cast as Rick Bryan in a 9/11 docufilm for The Discovery Channel, Rick Bryan was the last ever survivor of the second tower in the 9/11 attacks.

He was then cast as (Francis Double), Ensemble, Understudy Barman & Pickford Swing in The National Theatre's SMASH HIT COMEDY 'One Man, Two Guvnors' starring James Corden. Gareth was in the Original Cast at The National Theatre, then embarked on the UK TOUR and transferred with the show to The Adelphi Theatre in London’s West End.

Gareth then completed his third successful year on All Star Family Fortunes playing Vernon Kay's comedy assistant (shown throughout year) and can be seen in an episode of 'Kevin Bishops Britain' playing James Corden.

In May 2012, Gareth filmed an episode of 'Britain Unzipped' playing Humpty Bumpty and is currently writing with West End Star Louise Dearman (who he met when they appeared in Cats together in 2009). They have just completed writing their pilot Sketch Show, which has been extremely well received by huge industry professionals.

In September 2012 Gareth completed the feature film 'Cuban Fury' due for release in March 2013 and is currently the animated face of 'Vinnie in the 'Foxes Biscuit' Adverts in the UK.

In February 2013 Gareth flew to Madrid to be one of the new faces of the 'William Hill' commercials to be shown in Spain and online throughout 2013 & 2014.

He was cast as 'Orderly' in A Young Doctors Notebook starring Daniel Radcliffe.

​In  2014 Gareth was filmed in Disney's Major Feature Film 'Cinderella' playing the role of the 'Goose Coachman' starring Helena Bonham Carter, Cate Blanchett and is directed by Kenneth Branagh,

In 2015 Gareth returned to his welsh roots playing the role of 'Emlyn Llewellyn' in 'Stella' Series 4, again this is due for release in early 2015.

In 2016 Gareth was cast as Harry - The Security Guard in 'Ordinary Lies' and featured in 2 Episodes.

In 2017 Gareth was then cast in the BBC One thriller 'Requiem' playing the locksmith.

In late 2017 and early 2018 Gareth filmed the movie 'Christopher Robin' for Disney playing the role of the balloon seller, the movie stars Ewan McGregor who plays the title role.  

In the latter end of 2019 (prior tp COVID pandemic) Gareth was luck enough to be cast in AMAZON's exclusive Series 'The Feed', currently not show in the UK but played heavily in America and other countries.

Gareth is working on extremely exciting projects in the Comedy World at the moment and is the Entertainment Manager at a Cafe/ Cocktail bar in Chiswick..

Gareth Mason was born on 12th May 1982 in Reading, but grew up in Barry, Wales before moving to London where he currently resides.

As a youngster, Gareth joined Anwen Little Theatre as he had always enjoyed performing. At Anwen, he played the following roles: Babyface in Bugsy Malone, The Wizard in The Wizard of Oz, Mr Speck (Son of Spock) in Dazzle and Fat Sam in Bugsy Malone.

Gareth then went on to study drama at School and then did a BTEC National Diploma in Performing Arts at Coleg Glan Hafren in Cardiff.