Not one to miss out on an opportunity to promote himself, McGregor quickly took to Sweeney’s Instagram this weekend, after she posted a photo of herself with the caption: ‘IMMACULATE march 22nd.’

In response, the Irishman wrote: ‘Road House March 21st’, and quickly racked up over 5,000 likes, becoming the top comment on the post.

Sydney Sweeney stunned on the red carpet for the premiere of her new film Immaculate

Conor McGregor, 35, is starring in a movie of his own, alongside Jake Gyllenhaal, 43

And McGregor hijacked Sweeney’s Instagram on Saturday for some shameless self-promotion

Needless to say, his like count faded into insignificance when compared with Sweeney’s original post, which had totaled 1.25 million as of Sunday morning.

In the Instagram post, Sweeney, 26, wore a daring white dress on the red carpet to promote the movie, which sees her play in a nun in a psychological horror.

McGregor, meanwhile, stars alongside Jake Gyllenhaal in action movie Road House – and was praised by fans for his efforts in promoting the movie online.

One called him a ‘marketing genius’ for hijacking Sweeney’s popularity, while another added: ‘The promo on the promo is genius.’

Sweeney’s fame has shot up this year, and she even hosted Saturday Night Live this month

The 26-year-old actress was joined by two of her grandmothers and mother Lisa (pictured left) at the Los Angeles premiere of her thriller Immaculate on Friday

Sweeney grins during her Saturday Night Live hosting gig in New York City on March 2

Although his acting debut is big news, McGregor is insistent that his first priority is a return to the UFC, and while a fight with Michael Chandler has been in the works for more than a year, there is still no date for the bout.

Fans are growing increasingly concerned that McGregor will never return to the sport at the age of 35, but he insisted recently that ‘negotiations are ongoing’.

When recently asked if Road House was going to be the start of his acting career, McGregor revealed he plans to ‘get back into fighting shape’ so he can compete as a UFC fighter again.

He admitted that his filming schedule for Road House was grueling and went on: ‘It was hard work, and I’m used to hard work, but the schedule was intense.

‘I’m not sure if I will go through it again, but it’s in the bank, it’s in the history books. Money can come and go, but this film will be there forever.’

The UFC star is set to make his acting debut in a movie that comes out a day before Sweeney’s

Gyllenhaal bared his sculpted torso in a smoldering poster for the upcoming Road House

Many film critics have praised the UFC star for his debut acting appearance, with some saying he could be the next Arnold Schwarzenegger.

Indie Wire’s film critic Christian Zilko said: ‘McGregor steals every scene he’s in.

‘It’s unclear how much of what he does is actually acting, as he simply plays a rowdy and charismatic Irishman who likes to hit people and show off his ridiculous tattoos.

‘But his first acting role could establish him as his generation’s Arnold Schwarzenegger.’