Disgraced Sydney Roosters NRL star Mitchell Pearce has left Australia for rehabilitation overseas in a bid to overcome his alcohol problem.

Less than 24 hours after tearfully apologising for his drunken antics that were captured on an Australia Day video, Pearce left Sydney with mum Terri on Friday night to check into an undisclosed overseas clinic.

“The club’s concerns for Mitchell’s welfare remain paramount as he seeks treatment,” the club said.

Pearce’s departure comes after revelations the NRL is investigating a series of texts between alleged fellow partygoers that appear to make reference to drug use on the night in question.

The text exchange has yet to be authenticated, but refers to the distribution of “liney lineys”.

Liney lineys is believed to be a drug reference.

The messages are understood to include one person who was with Pearce and a number of Roosters players at the Royal Oak Hotel, where they had kicked on after a club-sanctioned harbour cruise that day.

The party then carried on to an apartment in Bondi, where Pearce was filmed attempting to kiss a woman, simulating a sex act with a dog and allegedly urinating on a couch.

The texts reveal a person named “Jack” had captured the footage of Pearce in the apartment and considered selling it to “end his career”.

According to the texts, they weren’t friends of Pearce.

“No none of us were – they were with us at the oak and they were pretty normal – giving out liney lineys and then they jumped a cab with me back to hers and went … ape shit! Jack just sat there filming it all,” the text read.

A clearly shaken Pearce fronted reporters on Friday for the first time since the emergence of the video.

“I would like to unreservedly apologise to everyone for my actions over the last couple of days,” said Pearce, who did not take questions from reporters.

“My behaviour was unacceptable, I’m embarrassed and take full responsibility for my actions.

“I acknowledge that I have a problem with alcohol and it’s something I need to address.

“It’s not an excuse but a realisation that I finally need help.

“Together with the club, I’m working on a solution to address these issues and it will come out in the next couple of days.”

The NRL is under intense pressure to sack Pearce, but it is increasingly likely he will be spared the axe and slapped with a lengthy suspension.

He is also expected to incur a hefty fine, lose his co-captaincy and face possible banishment from the NSW State of Origin team.

Roosters recruits Dale Copley and Jayden Nikorima are also facing sanctions from the club.

The pair, signed from Brisbane in the off-season, were at the party and captured in the infamous video.

They will be asked why they did not go home after a Roosters official gave them cab dockets and instead partied on into the early morning.

There is no suggestion of any illicit drug use by Pearce, other Roosters players or other people at the party on that night.