Dennis Quaid with wife Kimberly, son Thomas, and daughter Zoe on February 3, 2011 in Los Angeles, California. Credit:

At almost 5 years old, Thomas and Zoe Quaid sure are keeping actor dad Dennis on his toes.

"They're entering into what I call the 'age of reason.' Out of their two and three year olds, where you cannot reason with them, and now that they're in preschool they're like real big kids now," Vegas actor Quaid told Us Weekly at Monday's Los Angeles Confidential Men's Issue party of his children with wife of seven years Kimberly.

Citing buckling their own seatbelts as a major recent milestone, proud papa Quaid, 57, tells Us his tykes are quickly developing their own unique personalities -- and fashion sense.

"They're very different! [Thomas is] always running for mayor because he's just a very happy kid and very trusting of everybody, very gregarious!" reports the actor. "[Zoe] is a really smart girl and she is a very girly girl! She was into fashion when she was 3 months old! She would look at my hat and go, 'no!'"

Once Thomas and Zoe get older, Quaid intends to show them his repertoire of films, starting with 1998's The Parent Trap, in which he costarred with Lindsay Lohan.

"Right now they think that my job is to be on the side of billboards on the side of the bus!" Quaid, who has a teenage son, Hunger Games actor Jack, 19, with ex Meg Ryan, joked of his little ones.