Just like Amazon's 'The Idea of You', this film visits the age-gap romance of the older woman (who's 'normal') with the younger man (who's famous).
Here, in this iteration, the plot is split between the character Zara Ford and her aspirations to produce films and using her celebrity boss, Chris Cole, to get there and her single mother, author/writer Brooke Harwood, who discovers an exciting connection with her daughter's boss.
Romance movies are, at its core, simple tropes and relies on those standard cliches. That's what we love about romance movies. What elevates the basic romance is the chemistry and overall plot that at least tries to throw some 'thing' to make it less typical and a tad more elevated or has decent acting.
Sadly, A Family Affair fails on many fronts. My rating is purely for Kathy Bates as the MIL to Kidman's character, whose husband has been gone 10+ years before, and the daughter, Zara Ford, played by Joey King, who is the PA to an obnoxious, shallow and selfish self-proclaimed movie star.
The number one problem are our leads. The age-gap, a trope in and of itself, is no the problem. There is absolutely zero chemistry between Kidman (who plays Brook Harwood) and Efron (who plays Chris Cole). Not to mention that their very faces are terribly distracting--in that, they've both had so much work done, you can't help but notice it and not really get past it. If there had been decent chemistry between them, all that could be forgiven to a degree.
The second issue is the acting. It's...rather terrible. Especially by Kidman and Efron, the latter whose ability is more Hallmark B-level skills. The only saving grace was King and Bates, who made it even remotely watchable.
I think the plot angle of King's character is actually a fun idea and King executes it brilliantly. She carries the movie. However, the rest of the plot is pretty miserable and nothing to really swoon at.
Also, because this movie came out so soon after Anne Hathaway's similar movie, which also lacked chemistry between its leads, it takes the general winds out of this movie. Ultimately, this did have potential as the plot isn't bad. Who knew that Efron and Kidman would suck and actually hurt the movie vs make it better?
If anything, watch it for Joey King and Kathy Bates.