The 22-year-old singer, who was most recently linked to Victoria's Secret model Stella Maxwell, is seeing the 43-year-old comedian in recent weeks, reported Us magazine.
The duo have been friends for many years. They were first spotted dancing at a party in Los Angeles in December 2013.
Cyrus, who split from former fiance Liam Hemsworth in 2013, recently denied that she was in a serious relationship with Stella.