Elton John is remembering his friend, mentor and "inspiration" today, Leon Russell, who died in his sleep over the weekend.

"He was a mentor, inspiration & so kind to me. I loved him and always will," John wrote on Twitter. John and Russell collaborated on the album The Union in 2010, right before Russell was inducted into the Rock and Roll Hall of Fame the next year.

Other stars paid tribute to the late singer/songwriter on Twitter Sunday.

Steve Martin wanted followers to listen to Russell's "masterpiece," A Song For You.

Whoopi Goldberg posted about the "amazing musician."

LeVar Burton acknowledged Russell's "masterful keyboard prowess and gravelly soulful singing."

Kings of Leon's Nathan Followill tweeted about Russell, a "legend."