They have since been pictured on various occasions partying together in glamorous cities like New York and Los Angeles.
However, photographs spanning from Wednesday last week to Sunday show the two women sharing an extended period of intimacy together.
The two were seen shopping while locked in intense conversation.
While photos from Sunday see 26-year-old Stella visiting Kristen, also 26, on set of her film directed by Craig William Macneill.
The Twilight star has a quite the dating resume, from her controversial romance with Robert Pattinson to her off-on relationship with Soko.
Stella was also involved in a high-profile romance of her own last year when she briefly dated outlandish singer Miley.
The catwalk pin-up has spoken openly about their fling in the past, joking during an interview with V Magazine earlier this year that the two 'met through Grindr', the gay and bisexual dating app.
In reality, the singer and the swimwear model, who is Northern Irish but was bought up in Belgium and New Zealand, met through the star's assistant and close friend Cheyne Thomas.
Stella was pictured sharing a passionate kiss with the former Disney star when she took a break from filming her one of her music videos in Hollywood back in July, though they were never official.
