Trouble in the air for Kidman and Urban?

Either they were both really nervous or there was some tension in the air for Nicole Kidman and Keith Urban on their first public outing as a couple.

The lovebirds seemed to be a bit distant even though they were seated next to each other at a music event in the US on Tuesday night.

Witnesses reported seeing Kidman exchange a few words with Keith Urban before he looked away uncomfortably for a short while. As he turned back towards her, he was given a quick glare.

The couple - who were at the MusiCares Person of the Year Award ceremony in honour of American music legend James Taylor - rubbed shoulders with musicians Sting, Paul Simon, Carole King and Bruce Springsteen, who all performed at the tribute dinner.

Meanwhile, the actress is set to reunite with filmmaker Baz Luhrmann in an Australian epic also starring Russell Crowe. Filming is set to start in July or August.