Robin Thicke's lengthy campaign to win back his estranged wife Paula Patton, who he's been married to for eight years, has failed as the actress finally filed for divorce after the pair announced their separation back in February.

Robin Thicke
Patton and Thicke's eight-year marriage is finally over

Patton, 38, who shares a 4-year-old son, Julian, with Thicke, cited "irreconcilable differences" in divorce papers filed in Los Angeles last week, People magazine reports, and is requesting joint custody.

After months of speculation that the 'Blurred Lines' singer had cheated on the '2 Guns' actress, they eventually parted ways eight months ago, releasing a statement at the time that read, "We will always love each other and be best friends, however, we have mutually decided to separate at this time."

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It could be said confirmation that the couple were never going to reconcile happened just over two months ago when they put their Bel Air family home up for sale, with an asking price of almost $3 million.

Thicke's most romantic gesture to win Patton back came in June when he announced his seventh studio album would be called 'Paula.' However, this was also a huge failure as the record only managed to sell 530 copies in the U.K., and only shifting 25,000 in its debut week.

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And only last month, the 37 year-old singer may have revealed the main reason for his and Patton's sudden split. Thicke admitted he was "high and drunk" during every interview he gave in 2013, confessing, "I had a drug and alcohol problem for the year and I didn't do a sober interview. So I don't recall many things that I said."