The singer, who attended the White House Correspondents' Association dinner in Washington DC last night, has insisted that the First Lady is a "confident" and "powerful" woman.
Speaking to People, Simpson said: "She's such an incredible woman, and she's with such a powerful man.
"Everything she does she exudes confidence. I'm really just here to celebrate her."
Other stars at the annual gala included Kristin Davis, Michael Douglas and Bradley Cooper.
