The charge star crime-fighting actor didn't see coming

The Mentalist didn't see it coming.

Simon Baker earned fame in a hit television show as Patrick Jane, a highly perceptive crime consultant.

Unfortunately for The Mentalist star life has not imitated art, with Baker unaware police had been following him before he was charged with drink driving in NSW.

The Australian actor brought a touch of Hollywood to a small NSW Northern Rivers town on Wednesday when he appeared in court for sentencing.

Baker was met by a media scrum at Mullumbimby Local Court wearing a sage green suit.

The 55-year-old was first seen by police driving along Bangalow Road at nearby Bangalow about 2.10am on July 20, the court heard.

Baker's vehicle crossed the centre line of the road and was "accelerating and decelerating at speeds" as police followed for about 8km.

When they pulled him over, Baker told officers he had consumed four glasses of wine at a dinner from 6pm.

"(Baker) was very polite and co-operative ... extremely remorseful for his actions," Magistrate Kathy Crittenden said of the popular actor, who was the vehicle's sole occupant.

What happened next was "unusual", Ms Crittenden said.

A roadside breath test could not be completed because of a global tech outage, which meant police IT systems were offline.

"Ordinarily police would've proceeded with a breath analysis but they had to use the old-fashioned sobriety test," Ms Crittenden said.

Baker appeared unsteady on his feet and smelt of alcohol, the court was told.

The movie and TV star has since completed a certificate in a traffic offenders rehabilitation program.

Australian actor Simon Baker arrives at Mullumbimby Court House
Simon Baker was "very polite and co-operative ... extremely remorseful," a magistrate said. (Darren England/AAP PHOTOS)

Ms Crittenden said four character references had been tendered to the court about Baker's community contributions, significant remorse and his conduct being out of character.

"The court has little difficulty in finding that Mr Baker is remorseful for his offending and it is unlikely he will offend again," she said.

Baker, who previously pleaded guilty to driving under the influence of alcohol, received a nine-month good behaviour bond.

No conviction was recorded.

Baker did not speak to media outside court, walking to a car with his lawyer after the sentencing.

The actor is back in Australia after a stellar TV and movie career overseas.

His most prominent role was on The Mentalist, enjoying a seven-season run as the California Bureau of Investigation consultant who uses razor sharp observation skills to solve crime.

Australian actor Simon Baker arrives at Mullumbimby Court House
Simon Baker is back in Australia after a successful TV and movie career overseas. (Darren England/AAP PHOTOS)

It earned him a number of award nominations, including a Primetime Emmy nod for outstanding lead actor in a drama series.

Baker earlier featured in classic Australian TV programs including Home and Away and Heartbreak High, earning him Best New Talent at the 1993 Logies.

He made a successful move to the United States, landing roles in films such as The Devil Wears Prada and Academy Award winner L.A. Confidential.

Baker was given a star on the Hollywood Walk of Fame in 2013.

He recently starred in the Netflix series Boy Swallows Universe which won several Logies.