And now the US singer has apologised for her performance.

The singer told TMZ: "I've always been honoured and proud to perform the national anthem and last night I wanted to try something special for the NBA.

"I'm a risk taker artistically, but clearly this rendition didn't strike the intended tone."

She added: "I love this country and honestly tried my best."

Star-mangled banner?

Social media went into meltdown as people reacted to the former Black-Eyed Peas singer's unusual version.

ESPN journalist Jemele Hill tweeted a clip from TNT's coverage of the event in Los Angeles, pointing out even NBA player Draymond Green could not keep a straight face.

Memes were soon circulating, comparisons to previous singers were abound and #Fergie was trending on Twitter.

Some thought she was copying the breathy style used by Marilyn Monroe when she famously sang Happy Birthday to President Kennedy.

Another joked it would take some time to recover.

It's not the first time Fergie has sung the US national anthem in public.

She performed the Star-Spangled Banner in front of the Obamas in 2009 at the White House's annual Easter Egg Roll.

Suffice to say, it was a much more traditional rendition and attracted far less attention.