American Idol runner-up Adam Lambert has reportedly been arrested outside a gay bar in Helsinki after a violent fight with his boyfriend.

Lambert, 29, is said to have fought with Sauli Koskinen, a Finnish reality TV star, outside a bar called Don’t Tell Momma in the country’s capital city. Reports appear to have originated from gossip blogger Perez Hilton’s site.

Following the fight, which was reported to have taken place at 4am this morning, the pair are believed to still be in police custody in separate police stations.

Lambert has not updated his Twitter profile since yesterday, and his management has so far issued no comment.

He has been in a relationship with Koskinen since 2010, and lives with the Finnish former Big Brother winner. Last year The Times said he was the first openly gay mainstream pop artist to launch a career on a major label in the United States.

Lambert rose to fame after being named the runner-up in the eighth season of American Idol in 2009. He subsequently came out officially in an interview with Rolling Stone.

The first single from Lambert’s second album was released this week, prompting suggestions online that the incident may have been a publicity stunt.

In late 2009, Lambert had several television appearances cancelled after his performance at the American Music Awards drew 1,500 complaints.

The routine included a gay kiss and simulated oral sex with a dancer.

He subsequently said the performance has “gone too far”.