Zac Efron shares hilarious behind-the-scenes clip of Joey King doing her own skull-knock stunt in their rom-com A Family Affair with Nicole Kidman

Zac Efron shared a hilarious behind-the-scenes clip of Joey King impressively doing her own stunt in their new romantic comedy A Family Affair.

The movie features Zac as fictional movie star Chris Cole, Joey as his harried personal assistant Zara and Nicole Kidman as Zara's beautiful mother Brooke.

A wrench gets thrown into Zara's life when she wanders into her Brooke's bedroom and is confronted with the sight of Chris and her mother having sex.

Zara suppresses her vomit, screams and tries to flee the room,  only to knock her skull on the doorframe and fall down unconscious.

Now, in a rollicking new clip, Zac, 36, has lifted the curtain and shown his Instagram followers the way Joey did the head-hitting stunt herself.

Zac Efron shared a hilarious behind-the-scenes clip of Joey King impressively doing her own stunt in their new romantic comedy A Family Affair

Zac Efron shared a hilarious behind-the-scenes clip of Joey King impressively doing her own stunt in their new romantic comedy A Family Affair

Using his phone, Zac filmed from the bed as Joey entered the room in character and mimed gagging at the sight of the scene in front of her.

She then let out an earsplitting scene and performed the skull-knock stunt so perfectly that an observer might worry she was actually hurt.

Luckily, the realism was only the result of Joey's professional skills, as she quickly rose to her feet once: 'Cut!' was called.

Her co-stars seemed especially impressed with her abilities, as Nicole said: 'That's my girl!' with a grin and Zac could not hold back his laughter.

Meanwhile Joey sauntered towards the bed, cackling and saying: 'Oh my God!' as Zac warmly told her she had been 'so good' at performing the stunt.

Joey recently gushed that working with Nicole was 'very natural, very easy, and always fun,' in a joint interview with Zac for Moviefone.

'Nicole's just the best. She's the sweetest and full of love,' Joey continued, adding that her co-star was 'so fantastic. It's hard to encapsulate what an angel she is in terms of just how I admire her.'

Joey also appreciated the experience of 'becoming friendly with her. She's just truly so special. I’m so lucky to work with her and Zac, they're both fantastic.'

The movie features Zac as fictional movie star Chris Cole, Joey as his harried personal assistant Zara and Nicole Kidman as Zara's beautiful mother Brooke

The movie features Zac as fictional movie star Chris Cole, Joey as his harried personal assistant Zara and Nicole Kidman as Zara's beautiful mother Brooke

A wrench gets thrown into Zara's life when she wanders into her Brooke's bedroom and is confronted with the sight of Chris and her mother having sex

A wrench gets thrown into Zara's life when she wanders into her Brooke's bedroom and is confronted with the sight of Chris and her mother having sex

Zara suppresses her vomit, screams and tries to flee the room, only to knock her skull on the doorframe and fall down unconscious
Now, in a rollicking new clip, Zac, 36, has lifted the curtain and shown his Instagram followers the way Joey did the head-hitting stunt herself

Zara suppresses her vomit, screams and tries to flee the room, only to knock her skull on the doorframe and fall down unconscious

Her co-stars seemed especially impressed with her abilities, as Nicole said: 'That's my girl!' with a grin and Zac could not hold back his laughter

Her co-stars seemed especially impressed with her abilities, as Nicole said: 'That's my girl!' with a grin and Zac could not hold back his laughter

A Family Affair was directed by Richard LaGravanese, who has previously helmed such classics as The Bridges Of Madison County and The Fisher King

A Family Affair was directed by Richard LaGravanese, who has previously helmed such classics as The Bridges Of Madison County and The Fisher King

Zac has shared that he had 'fun' sending up the experience of being a movie star, with all the accompanying anxieties and diva behavior

Zac has shared that he had 'fun' sending up the experience of being a movie star, with all the accompanying anxieties and diva behavior

Zac meanwhile shared that he had 'fun' sending up the experience of being a movie star, with all the accompanying anxieties and diva behavior.

'I guess, I got to just amplify a lot of feelings and things that I've experienced over the course of my career, in a very fun way and just jab at it a little bit,' he confessed.

A Family Affair was directed by Richard LaGravanese, who has previously helmed such classics as The Bridges Of Madison County and The Fisher King.

He also wrote the screenplay for the 1996 romantic comedy The Mirror Has Two Faces, which Barbra Streisand directed and starred in opposite a formidable cast including Jeff Bridges, Pierce Brosnan, Lauren Bacall and Mimi Rogers.

A Family Affair, released on Netflix this Friday, was less well-received than those earlier projects, polarizing the critics to the tune of 50% on Rotten Tomatoes