Lil' Wayne made a surprise appearance at a Jay-Z concert in New York last night – just hours after his prison sentencing was delayed for the second time.

The rapper, real name Dwayne Carter, was expected to be jailed for up to a year on Tuesday for gun possession.

But a courthouse fire meant proceedings had to be postponed again.

According to MTV, Lil' Wayne emerged onstage at Madison Square Garden during support act and Young Money labelmate Young Jeezy's opening slot.

The pair were joined on a rendition of 'I'm Goin' In' by Drake and Nicki Minaj, which sent fans wild.

"We with you 100 percent," Young Money told Lil' Wayne on stage.

As previously reported, Lil' Wayne's sentencing was delayed yesterday after a ground-floor fire broke out mid-morning at the Lower Manhattan courthouse where he was due to be setenced.

The rapper was originally due to begin his prison term in February, but sentencing was delayed to allow him to complete dental surgery.

Lil' Wayne pleaded guilty to attempted gun possession at a court hearing last October.

(by Jason Gregory)