LOS ANGELES (AFP) - Lil Nas X, Lady Gaga, Beyonce and... Michelle Obama?

Yep.

The former United States first lady can now add Grammy winner to her resume, after snagging the award on music's biggest night for Best Spoken Word Album, for the audiobook of her memoir Becoming.

Her win on Sunday (Jan 26) gives the Obama household its third Grammy: former president Barack Obama has already snagged two Grammys in the same category for his books.

She faced an eccentric group of rivals that include Michael Diamond and Adam Horovitz of the Beastie Boys for Beastie Boys Book and John Waters, the director-performer known for his transgressive cult films, for Mr Know-It-All.

Released in late 2018, Becoming saw Mrs Obama slam President Donald Trump for questioning her husband's citizenship and promoting the notion that he was born abroad.

"The whole (birther) thing was crazy and mean-spirited, of course, its underlying bigotry and xenophobia hardly concealed," she wrote.

America's first black first lady also dug into her personal life in her book, expounding on issues including a miscarriage, using in-vitro fertilisation to conceive her daughters and marriage counselling.