The 22-year-old singer and the model are said to have been dating "for months" and are known to friends as "a couple", reported Female First.
"They hold hands and hug and are very comfortable together. They're definitely together," a source said.
The "Wrecking Ball" hitmaker and the 24-year-old model have apparently been spending a lot of time together since the singer split from Patrick Schwarzenegger in March.
Cyrus had also recently opened up about her experiences of dating both men and women and recalled opening up about her sexuality to her mother when she was 14.