Actor Robert Downey Jr. is ready to fulfill his civic duty by serving as an alternate juror in a car accident case, reports said.

In effect, the actor is an understudy juror, who will be asked to step up in case an actual jury member is excused before the proceedings of the case are over. Reports said that he was chosen because “everyone just thought he was a fair guy,” a source connected with the case told TMZ. The source also added that the star simply identified himself as Robert Downey, saying he was in the film industry.

Downey, who is best known for his role as Iron Man, has been in Los Angeles since Monday, even though the jury is expected to start deliberations Friday, TMZ reported.

The accident reportedly does not involve “horrific” injuries with $50,000 on the line, in the best case scenario. Two biomechanical engineers are reportedly testifying, apart from the two drivers involved, and 4 eyewitnesses.

Downey, who topped Forbes’ list of the highest-paid actors in 2015 with $80 million, will only be paid $15 a day for his role on the jury. According to the Forbes' 2016 list, the actor's earnings fell 58 percent, putting him at No. 86.

Journalist Katie Couric was excused from jury duty in a separate case last week after she was reportedly “too inquisitive” in the matter. The actor, however, was reported to be attentive and open during the trial, with a source saying: “He actually seems happy to be here.”

California Governor Jerry Brown late last year expunged Downey’s drug-related convictions from the 1990s, clearing the actor’s criminal record.