Adam Levine has admitted it will always be hard for Maroon 5 to perform their 2019 song Memories.

Levine wrote the song, the lead single from their album Jordi, about losing a loved one following the death of his longtime friend and the band's manager, Jordan 'Jordi' Feldstein, in December 2017.

The emotional song features on the setlist for Maroon 5's current M5LV Las Vegas residency, and Levine explained that it is a challenging but necessary part of the show.

"It's always hard (to perform that song). It'll never be easy," he shared. "It's not easy to share that part of us, but it's important and necessary to talk about it at a certain point. I think enough time had passed where we had been able to process some amount of it to be able to share it with people and celebrate who he was and who he still is to us and our history."

Before Memories is performed during the residency, Feldstein is honoured on the theatre's screens. The music manager, who was also the brother of actors Jonah Hill and Beanie Feldstein, passed away at the age of 40 due to pulmonary thromboembolism and deep leg vein thrombosis.

Maroon 5 kicked off the M5LV residency at Dolby Live at the Park MGM Las Vegas in late March and they are due to perform select dates through to 12 August.