"Jenny and I have just ended our 5yr relationship," the actor wrote. "I'm grateful 4 the many blessings we've shared and I wish her the very best! S'okay! ?;^>"
Within a half hour of Jim posting the news, Jenny too Tweeted about their break up.
"Im so grateful for the years Jim and I had together. I will stay committed to Jane and will always keep Jim as a leading man in my heart," she wrote. Jane is Jim's adult daughter from his first marriage.
This isn't the first time Carrey has broken major personal news through Twitter.
In November 2009, he shared the news of daughter Jane's wedding via Tweet.
"my Jane is a married women [sic]. days ago her and me new son in law alex got hitched," Jim Tweeted late last year. "the day was simply perfect… lots of love there."
He also Tweeted the first photo of his first grandson, Jackson Riely Santana, in February.
Jim and Jenny began dating in 2005.
The couple regularly appeared on red carpets together and at autism events, a cause close to Jenny's heart, as her son Evan was previously diagnosed with the condition.
While the two appeared to be a strong couple in Hollywood, Jenny said in December 2009, during an appearance on "The View" that the couple had no plans to walk down the aisle.
"I had a dream last night that I left him at the altar… because I don't want to get married," Jenny told "The View" panel at the time.
"I think we are married we don't need a piece of paper," she added. "Maybe one day when we're 80 and I need the tax write-off [we'll tie the knot]."
At the time, Jenny said she was smitten with the star.
"I'm madly in love with him," she said. "He's the greatest guy."
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