Mary-Kate Olsen and Olivier Sarkozy attend the Dallas Mavericks vs New York Knicks game at Madison Square Garden on November 9, 2012 in New York City. Credit: James Devaney/

Even Olivier Sarkozy's ex-wife is a fan of Mary-Kate Olsen!

In the new issue of Us Weekly (on stands Friday), a source says the fashion designer, 26, has won over her boyfriend of seven months' former spouse. "Mary-Kate always includes her," a source says of Charlotte Sarkozy, 42, who split with the French financier in 2010 after 13 years of marriage.

"MK asks her permission about things that concern the kids [Julien, 11, and Margot, 9]," the source adds. "So Charlotte loves her!"

Olsen and her boyfriend, 42 -- the managing director of the Carlyle Group's global financial services division and half-brother of the former president of France, Nicolas Sarkozy -- currently live in a $6.25 million East Village townhouse. "They are madly in love," an insider previously told Us.

Ashley Olsen's famous twin sister has said little about their May-December romance, though she did tell WSJ. Magazine she doesn't pay attention to doubters. "Everyone has an opinion," Olsen said of their 16-year age difference. "I find it's better to focus on what's in front of you and to keep putting one foot in front of the other."