A North Korean singer said to be leader Kim Jong-Un's ex-girlfriend and rumoured to have been executed last year has appeared on state television, apparently alive and well.

   Pyongyang's state TV showed Hyon Song-Wol, the head of a band known as Moranbong, delivering a speech at a national art workers rally in Pyongyang on Friday.

   She expressed gratitude for Kim's leadership and pledged to work harder to "stoke up the flame for art and creative work".

   Her appearance came after months of speculation about whether or not she was alive.

   Japan's Asahi Shimbun and South Korean media said in September that Hyon, members of the Unhasu Orchestra and other state musicians had been executed by firing squad for taping themselves having sex.

   South Korea's spy chief Nam Jae-Joon added weight to the reports when he said in October that he was "aware" of the alleged execution.

   "We are aware of the execution of some 10 people associated with the Unhasu Orchestra", two lawmakers quoted Nam as saying at a closed door parliamentary session, according to Yonhap news agency.

   The Asahi said the rare execution of state performers had been ordered to prevent rumours spreading about the supposedly decadent lifestyle of North Korean first lady Ri Sol-Ju while she was an entertainer.

   North Korea angrily denied the reports, calling them an "unpardonable" crime.

   The North's state news agency KCNA said the reports were the work of "psychopaths" and "confrontation maniacs" in the South Korean government and media.

   "This is an unpardonable, hideous provocation hurting the dignity of the supreme leadership," a KCNA commentary said in September.

   In an apparent attempt to prove the rumours untrue, North Korean radio in October aired a performance by the orchestra. (AFP)