‘Grandfathered,’ surprisingly fresh

As a movie and TV premise, the confirmed bachelor who suddenly learns he’s a father has been around a long time but isn’t as worn out as one might expect.

The same could be said for John Stamos, whose new sitcom, “Grandfathered,” puts a twist on the premise that is slighter than one might expect.

The twist is that the child is an adult with a child of his own, explaining the show’s title. But most of the resulting comedy, as well as the mild drama, is familiar from movies and TV shows with the original premise.

Stamos, a sitcom pro who has grown more charming over the years, makes the familiar setups work. The show’s newish elements — the main character’s vanity about aging and his mentoring relationship with his nerdy adult son — freshen the mix adequately.

In “Grandfathered,” premiering on Fox this Tuesday, Sept. 29, at 8 p.m., Stamos plays Jimmy, a happily single guy who owns and operates a trendy L.A. restaurant. One of his most successful pickup lines is telling women that he would give it all up to have a family.

One day, an unemployed 25-year-old 3-D designer named Gerald (Josh Peck) shows up at the restaurant and says that not only is he Jimmy’s son but he has a toddler daughter of his own, Edie.

Gerald fathered his child with Vanessa (Christina Milian) in a one-night stand. She thinks of him as just a friend, and he’d like Jimmy’s help in changing that.

But Gerald is also looking for a relationship with Jimmy. “The other day,” he says, “I came across a BuzzFeed listicle called ’28 Reasons Why Having a Dad Is the Best.’ By No. 12, I was crying so hard I was dehydrated.”

The idea that 50-year-old men are urbane and well dressed and 25-year-old men are feckless and schlubby is debatable. After all, 25 years ago, Jimmy’s generation gave rise to the term “slacker.”

Jimmy contacts Gerald’s mother, Sara (Paget Brewster), who he hasn’t spoken to in 26 years. She reminds him that when they were together, he refused to refer to her as his girlfriend and wouldn’t let her leave a toothbrush at his place.

After threatening Jimmy with violence if he hurts Gerald or Edie, she says, “You look great, by the way. That deal with the devil really paid off.”

The script, by Daniel Chun, settles for the usual clichés about men’s general incompetence at child care. There’s an overt reference to Dustin Hoffman in “Kramer vs. Kramer” and a babysitting scene that is strongly reminiscent of “Tootsie,” minus the drag.

But the Jimmy-Gerald relationship is new for this sort of comedy, and Jimmy’s age provides for a few fresh jokes. Sara tricks him into admitting that he dyes his hair. When she asks if he has used Botox, he replies, “Yes, but not on my face.”

But the main focus of the show is likely to be Jimmy moving one step toward and two steps back from being a responsible and loving parent while he and Sara warily circle each other.

A twist at the end is just sentimental enough, and Stamos fans will appreciate a brief celebrity cameo.

Both the principals and the supporting players manage to make the dialogue a little funnier than it is.

“Grandfathered” is one of those shows that are on the line between worth watching and not worth watching. This time, we prefer to see the house as half full.