Andy Murray: British number one splits with coach Ivan Lendl
British number one Andy Murray has split with coach Ivan Lendl for a second time by "mutual agreement".
The Scot won Wimbledon, the US Open and Olympic gold during two years with Lendl from 2012 to 2014.
Murray was then coached by Amelie Mauresmo before turning back to Lendl in 2016, winning his second Wimbledon title, a second Olympic gold and becoming world number one that year.
"I'm thankful to Ivan for his help and guidance over the years," Murray said.
"We've had great success and learned a lot as a team. My focus now is on getting ready for Australia with the team I have in place and getting back to competing."
Former world number one and eight-time Grand Slam winner Lendl, 57, added: "I wish Andy well. We had a great run and a lot of fun."
Murray has been recovering from a hip injury, and his last competitive match was a Wimbledon quarter-final defeat by Sam Querrey in July.
He has since slipped to 16th in the world rankings, but earlier this month he played in a charity match against Roger Federer.
After losing 6-3 3-6 10-6, Murray said he "hoped" to return to competition at the Brisbane International in January.
The tournament is held two weeks before the Australian Open, the first Grand Slam of 2018, which gets under way on 15 January.
BBC tennis correspondent Russell Fuller
Murray and Lendl have spent very little time in each other's company this season as injury has forced the former world number one to spend so much time on the sidelines.
The partnership fizzled out first time around as Murray was returning from back surgery - and there is a clear parallel three and a half years on.
Murray was distraught when they split in 2014, having realised Lendl was not prepared to commit to the number of weeks on tour he required. This time, there is more a feeling the partnership has run its course.
This is the time where plans and contracts are put in place for the year ahead. And just because Lendl - who can be a hard taskmaster as well as an expensive addition to the payroll - was the right choice in 2012 and 2016 does not mean he is necessarily the right choice in 2018 when the 30-year-old's hip and schedule will have to be carefully managed.
Finding a figure of Lendl's stature to supplement the valuable work of Jamie Delgado is unlikely to be of pressing concern to Murray right now. First and foremost he craves fitness and the chance to be able to compete for the sport's major prizes once again.
Former British number one Tim Henman
It's not a surprise for me. They've had a massive amount of success together and I'm sure Andy and the whole team have learnt an enormous amount from Ivan.
They never actually saw a great deal of each other and I think right now the focus and attention is on Andy's hip and getting healthy again. He's got a great team in place.
Former British number one Andrew Castle
It's kind of a shame, Ivan Lendl is someone who will always be on the end of a phone and if Andy wants to call on him in the future, then he can.
I remain extremely worried about his hip and his future prospects. I've got my fingers crossed for him.