Michelle Obama spent her Saturday officiating a wedding in Chicago ahead of her highly anticipated book tour.

The former First Lady was in her hometown to oversee the wedding of the Chicago deputy mayor's daughter Stephanie Rivkin.

Mrs Obama married Rivkin, 27, and her groom Joel Sircus, 26, at the Theater on the Lake venue overlooking Lake Michigan on Saturday.

Footage from the ceremony shows Mrs Obama - wearing a floor-length black dress - standing in front of the happy couple while helping them repeat their vows.

Mrs Obama married Rivkin, 27, and her groom Joel Sircus, 26, at the Theater on the Lake venue overlooking Lake Michigan in Chicago on Saturday

'I promise to stand next to you and support you through all of my trials and triumphs,' she could be heard saying for the bride to repeat.

The bride's father, Robert S. Rivkin, has been deputy mayor of Chicago since sine July last year.

Rivkin and Sircus both graduated cum laude from Yale University.

The wedding is just one of the commitments Mrs Obama has in the coming weeks as she gets ready to kick off her stadium tour to launch her memoir, Becoming, on November 13.

Footage from the ceremony shows Mrs Obama standing in front of the happy couple while helping them repeat their vows

The happy couple, Rivkin and Sircus, both graduated cum laude from Yale University

Her appearances will be at venues of 15,000 and higher in capacity and tickets range from just under $30 to $3,000.

Mrs Obama is the first popular author to promote her book on a scale common for top musical performers, even using the entertainment company Live Nation.

'Mrs Obama wanted to make her tour as accessible as possible,' Tara Traub, senior vice president of Live Nation Touring, said in a statement Friday.

'The Live Nation team also knew the demand for her tour would be extraordinary. For these reasons, we knew an arena tour would maximize the number of people who will be able to join this unforgettable conversation with Mrs Obama.'