Aled and Katherine lead galaxy of stars for Christmas telly.
The former North Wales choirboy performs a duet with New Zealand soprano Hayley Westenra and pays a visit to the Welsh community in Patagonia, in Nadolig Aled.
It will be broadcast on Christmas Day night after a festive episode of Pobol y Cwm.
A host of other top musical stars including Bryn Terfel, Katherine Jenkins and Andrea Bocelli will also be performing on the Welsh language channel.
Other highlights are excerpts from Bryn Terfel's Faenol operatic gala along with pop star Bryn FOn's sell-out National Eisteddfod concert, carols from Llangollen and Caerphilly Castle and a round-up of the year's best contemporary sounds in Bandit.
Moving documentary Fy Mab yng Nghymru revisits Inge Hanson and John Pierce Jones a year on after the couple adopted a baby, Iwan Pyrs, from the troubled island of Haiti.
Award-winning journalist Tweli Griffiths returns to Africa in Nol i Ethiopia as S4C's 2005 Asia/Africa charity appeal draws to a close.
S4C's Christmas films include Mela, a charming tale of innocence and friendship, starring youngster Ceri Lewis and veteran actor Stewart Jones, and a feature-length version of the 1980s-based drama Emyn Roc a ROl.
A special edition of 04 Wal yn yr Haul sees homes and interiors supremo Aled Sam visit Welsh ex-pats in Singapore and Australia.
On New Year's Eve, Jonathan Davies, Eleri SiOn, Rowland Phillips and Nigel Owens celebrate an unforgettable year for Welsh rugby in Grand Slam style on chat show Jonathan.
On New Year's Day countryside magazine Cefn Gwlad, Dai Jones visits the families of Siwan Evans and Wyn Harries, the young couple set to marry in S4C's hit reality TV series, Y Briodas Fawr, which will be broadcast during the first week of January.
For younger viewers cartoons include Un SiOn Corn yn Ormod, and Uned 5: Gwobrwyo'r Goreuon reveals the names of Welsh children's favourite celebrities.
Iona Jones, S4C's Chief Executive says, "Top-class music certainly features prominently on S4C this Christmas, with a host of home-grown internationally-renowned stars making their mark, while drama, sport, documentary and children's programmes will ensure the whole family is entertained
Katherine Jenkins is among the big stars of S4C's Christmas line-up