Dennis Rodman and Kim Jong Un are apparently now friends, as the former NBA player just made the news by singing "Happy Birthday" to the North Korean leader. Rodman has been making multiple trips to North Korea since last year, calling it "basketball diplomacy" - setting up exhibition games with North Korean players and NBA players. On his latest visit to the capital Pyongyang yesterday, the controversial basketball player sang the Happy Birthday song to Kim during an exhibition featuring former NBA players. He did solo - his NBA comrades did not join in the surprise performance.

Social networking site Twitter is now overflowing with criticism for Rodman. One user tweeted, "Dennis Rodman has reached new levels of lunacy," while another said, "I hope this doesn't make me sound old, but that Dennis Rodman is a total loon!" Somebody else ranted, "I wish @dennisrodman would just stay in North Korea! He is such a mushmouth idiot! #crazyrodman."

The former Chicago Bulls star have started calling Kim his friend after his first visit back in February 2013. He traveled with some Harlem Globetrotters to do an exhibition game for the Korean leader, who is known to be a basketball fan. Kim then met with him and the two dined together, striking up a very unlikely friendship.

This latest visit has drawn the most outrage, as it comes after North Korea's execution of Kim's uncle Jang Song Thaek, the country's second leader. The incident has caused even more tension between North Korea and the United States.

Rodman was also criticized for not pleading the case of Korean-American Kenneth Bae, who is currently being held captive in North Korea. This caused the eccentric basketball star to unleash a rant during an interview with CNN, saying, "I don't give a rat's ass what the hell you think. I'm saying to you, look at these guys here, look at them. They dared to do one thing, they came here."