It's Kim Jong Un's birthday (probably), but North Koreans aren't celebrating

Kim Jong Un reportedly turned 34 years old on Monday -- nobody knows for sure -- but North Koreans, known for their over-the-top festivities complete with fireworks displays, didn’t host their usual celebration for the despot’s birthday.

Kim’s birthday was notably omitted from North Korea’s official 2018 calendar, which had Monday marked as a regular working day, the BBC reported. Unlike his father and grandfather, the regime has never publicly confirmed the dictator’s birthday since he came into power in 2011.

The closest acknowledgement to Kim’s birthday was when former basketball player Dennis Rodman sang “Happy Birthday” to the leader four years ago at an exhibition basketball match in Pyongyang, the BBC reported. Video footage of the serenade showed Rodman, who often boasts about his friendship with Kim, singing the birthday song. But North Koreans watching were told Rodman was singing “a special song.”

For the former leaders, Kim Jong Il’s birthday was marked on Feb. 16 and referred to as the “Day of the Shining Star.” Kim’s grandfather and North Korea’s first dictator, Kim Il Sung, celebrated his birthday on April 15, known as the “Day of the Sun.”

KIM JONG UN'S BIZARRE NORTH KOREA PROPAGANDA PHOTOS

Some experts believed this year Kim’s birthday would be marked a national holiday after successful missile launches and its sixth nuclear test in 2017. However, a North Korean source told Daily NK Kim’s approval rating “dropped to a new low” after the regime was slapped with new sanctions following the September nuclear test.

North Korea's leader Kim Jong Un speaks during a New Year's Day speech in this photo released by North Korea's Korean Central News Agency (KCNA) in Pyongyang on January 1, 2018. KCNA / via REUTERS     ATTENTION EDITORS - THIS PICTURE WAS PROVIDED BY A THIRD PARTY. REUTERS IS UNABLE TO INDEPENDENTLY VERIFY THE AUTHENTICITY, CONTENT, LOCATION OR DATE OF THIS IMAGE. NO THIRD PARTY SALES. NOT FOR USE BY REUTERS THIRD PARTY DISTRIBUTORS. SOUTH KOREA OUT.     TPX IMAGES OF THE DAY - RC11B0782E80

Kim Jong Un last appeared during his New Year's Day address.  (Reuters)

"International sanctions, especially those instituted after the 6th nuclear test in September, have caused a lot of hardship for workers with many losing their jobs as a result of the gradual slowing of coal exports,” the source told Daily NK.

The unidentified source added: "As the government pushes propaganda about its nuclear and missile development while even the more successful merchants are losing jobs and going hungry this year, people would only ridicule Kim Jong Un if they saw his birthday had been made a holiday.”

Kim is believed to be 34 after his aunt, Ko Yong Suk, told the Washington Post the despot was born in 1984 — the same year she gave birth to her son.

Katherine Lam is a breaking and trending news digital producer for Fox News. Follow her on Twitter at @bykatherinelam