Rumors are swirling that Benji Madden and Miley Cyrus may be a couple after the pair was spotted together on Halloween and reportedly had a steamy makeout session.

While at Adam Lambert’s Halloween party in West Hollywood, the two artists “seemed really into each other,” a source tells DailyMail. “Soon they were flirting and talking very closely. Then they shared a kiss. They left Bootsy Bellows together around 1 a.m. They tried to be discreet by sharing a car with some other friends, but it was clear they were leaving as a couple.”

Cyrus, who'd dressed as Lil' Kim, tried to cover her face as she exited the party, but photographers were still able to snap a photo of her with Madden and others.

Madden was last said to be in a relationship with an unidentified brunette whom he had been dating since the end of 2012. The two were seen lip-locking back in April, but it is unclear if they have split up. Prior to that relationship, Madden, 34, was dating English singer-songwriter Eliza Doolittle.

Cyrus, meanwhile, had been engaged to actor Liam Hemsworth, but they split for good in September after dating off and on since 2009. Last month, she celebrated her appearance on "SNL" by reportedly hooking up later with 26-year-old photographer Theo Wenner, the son of Rolling Stone owner Jann Wenner. They were rumored to be an item, but judging from this latest report, it seems another man has grabbed Cyrus’ attention.