Blake Lively's sister breaks silence amid lawsuit against co-star Justin Baldoni

Blake Lively's sister has broken her silence after the actor filed a lawsuit against her It Ends With Us co-star Justin Baldoni.

The actors starred alongside each other in the film adaptation of Colleen Hoover's best-selling novel, with Baldoni also acting as the movie's director.

Shortly after the movie's release, speculation surrounding the pair's alleged 'friction' arose, while Lively also found herself being slammed online during the film's press tour.

Lively has since filed a lawsuit against her co-star, with the Gossip Girl star accusing Baldoni of 'other behaviors that were shocking and emotional distressing', as per the complaint.

Lively also accuses Baldoni of sexual harassment - something the Baldoni camp categorically denies.

Bryan Freedman, an attorney for Baldoni as well as Wayfarer Studios, told The Hollywood Reporter in a statement: "It is shameful that Ms. Lively and her representatives would make such serious and categorically false accusations against Mr. Baldoni, Wayfarer Studios and its representatives, as yet another desperate attempt to ‘fix’ her negative reputation which was garnered from her own remarks and actions during the campaign for the film; interviews and press activities that were observed publicly, in real time and unedited, which allowed for the internet to generate their own views and opinions."

Lively's sister Robyn initially shared a short statement on her Instagram story following Blake's lawsuit, reading: "FINALLY justice for my sister @BlakeLively."

She has since shared a longer response. She took to Instagram to share a screenshot of the New York Times article that detailed what Lively is claiming in the lawsuit.

"It calls out those behind the ruthless and nefarious smear campaign that aimed to take down my sister," Robyn penned.

"It also highlights the truth and what really happened, what she actually endured during the filming of It Ends With Us."

In part, the statement continued: "She is one of the kindest, most honest and loving humans I know. Blake isn’t a villain. She’s a mama bear to her core, a loving and supportive wife, a sister, a friend, and someone who worked her ass off on a film in abominable working conditions.

"The 'truth' in the tabloids is hardly ever what you think. But honesty prevails. Today is a good day. My gratitude is boundless for your kindness here and consideration for my sister.

"I’m so proud of her. Proud that she has handled herself with such grace and didn’t cave, that she didn’t allow herself to be silenced in the face of adversity and lies. I hope this gives others the strength to do the same."