Ellis, who is rated as one of the world’s best second-rowers asked the club for an early release, citing personal and family reasons.
“Whilst we are disappointed, we have granted Gareth his wish to return to England at the end of this year,’’ said Wests Tigers CEO Stephen Humphreys.
“Gareth has been an integral member of the Wests Tigers team in recent years. He has taken his game to another level under Club and Australian Test Coach Tim Sheens and is held in the highest esteem by everyone at Wests Tigers.
“Gareth will leave Wests Tigers with our blessing – and hopefully an NRL premiership.â€
Ellis, who turns 31 this year, made his debut for the Wests Tigers in 2009 and has played in 64 NRL games to date – as well as winning the Tigers Player of the Year award for three straight years, the only player to do so.
“I feel the time is right for me to return to England,’’ Ellis said.
“It was a difficult decision to make as I have really enjoyed my time at Wests Tigers. Everyone at the Club has been terrific to me and my family. I couldn’t ask for more.
“I have a young son now. My wife Rachael and I feel it is time to head home to our families at the end of this season.
“I can assure Wests Tigers supporters I will be giving it my all to ensure the team finishes high up as possible so we can give ourselves another strong chance of winning the Telstra Premiership.â€