Just months after [article id="1590236"]Madonna denied that her marriage was in trouble[/article], a British tabloid is reporting that she and husband Guy Ritchie are set to announce their split, "imminently."

The Sun reported on Wednesday (October 15) that a "highly placed source" confirmed that Madonna, 50, and Ritchie, 40, "just couldn't live together any more" and could "no longer bear to live with the pretence" of being a happily married couple.

While the singer's longtime publicist, Liz Rosenberg, could not be reached for comment, her London-based publicist told Reuters, "No comment."

Ritchie was not on hand in New York on Monday night at [article id="1596991"]the premiere of Madonna's directorial debut[/article], "Filth and Wisdom." When MTV News caught up with the singer at the event, she seemed in good spirits and showed no signs of any strife, though she did take time to explain her recent string of disses to Republican vice-presidential nominee Sarah Palin.

When similar rumors about a divorce emerged earlier this summer -- including allegations that Madonna had become [article id="1590474"]involved with New York Yankees player Alex Rodriguez[/article] -- the couple, who have been married for almost eight years, denied the reports.

"My husband and I are not planning on getting a divorce. I know Alex Rodriguez through Guy Oseary, who manages both of us," Madonna said in a statement at the time, during which Rodriguez was going through his own divorce proceedings. "I brought my kids to a Yankee game. I am not romantically involved in any way with Alex Rodriguez. I have nothing to do with the state of his marriage or what spiritual path he may choose to study."

Around the same time, rumors also emerged that Madonna had hired high-powered divorce attorney Fiona Shackleton, who represented Paul McCartney in his recent divorce proceedings.

The couple has a son, Rocco, and they adopted another boy, David Banda, from Malawi in 2006. Madonna has a 12-year-old daughter, Lourdes, from a previous relationship. The Sun reported that tensions between the couple have grown over the amount of time they devote to their respective careers and over Madonna's wish to adopt another child. The paper reported that the couple initially wanted to wait until next year to announce their separation -- after Madonna wraps up her Sticky and Sweet Tour -- but now want to finalize it before Christmas, which would have marked their eight wedding anniversary.

"It wasn't a matter of 'if' but 'when,' " the unnamed source reportedly told the paper. "They tried hard over the last few months, but their fighting was getting out of control. The final straw came before Madonna started her U.S. tour. Madonna wanted a highly stage-managed separation, with their split being announced when it was convenient for her. She didn't want the distraction while she is trying to concentrate on her tour."

The source went on to say that after a "series of rows" around Ritchie's birthday, Madonna stormed out of the house and Ritchie declared that they had to split now. The paper reported that Ritchie has flown back home from France, where he's filming "Sherlock Holmes" with Robert Downey Jr., to break the news to his parents. The couple is reportedly worth more than $520 million, most of which belongs to Madonna, with Ritchie bringing $35 million to the table. They have homes in London, Los Angeles and New York, as well as a 1,200-acre spread in Wiltshire, England.