Lionel Richie, John Legend

ABC's upcoming singing competition Duets is saving room for John Legend, who will replace Lionel Richie, the network announced Monday.

It is unclear why Richie dropped out of the project. He appeared as a guest mentor for Christina Aguilera's team on The Voice earlier this season and is currently promoting his new country CD, Tuskegee, which hit stores in March. Legend joins previously announced singers Kelly Clarkson, Sugarland's Jennifer Nettles and Robin Thicke. TRL alum Quddus will host.

Watch music videos from John Legend

Premiering on May 24, Duets will feature all four vocalists as they travel the country in search of the best undiscovered talent. Each of the chart-toppers will then pick two singers to duet with every week on the show in front of a live studio audience. In the end, one duet and one partner will win a recording contract.

"I'm thrilled to be part of Duets and I'm looking forward to finding an undiscovered gem out there. This is going be a lot of fun," Legend, 33, said in a statement.

ABC's Duets lands Kelly Clarkson, Robin Thicke, Lionel Richie, Jennifer Nettles

Legend, a seven-time Grammy winner, formerly sang back-up vocals for artists like Alicia Keys and Kanye West before releasing his debut studio album in 2004.

How do you think Legend will do on Duets?