WATCH LIVE: Michelle Obama hosts Mother's Day Tea at White House

The event is part of the duo's Joining Forces initiative and will honor military mothers.

Obama and Biden will also help military kids create Mother's Day cards in the State Dining Room. Afterward, the first and second lady will join the children in presenting their cards to their moms.

The pair hosted a similar event last year, where they praised military moms, honored their own mothers and touted the visiting children.

On Tuesday during a book signing at Politics & Prose Bookstore, Obama encouraged attendees to buy her book, American Grown: The Story of the White House Kitchen Garden and Gardens Across America, for Mother's Day.

"Those funds are going to help support the White House Kitchen Garden and other community gardens across this country. So buy away. It’s Mother’s Day. It’s coming up," she said to laughter.

Proceeds from the book go to the National Park Foundation. "I would say that I was going to give this as a gift to my mother, but she already has, like, 10 copies. But I might buy her another one just for the heck of it," Obama added.