The 14-year-old star's photograph with the 'Hotline Bling' hitmaker, which was taken when they were both working in Australia, went viral last November and she revealed that since their first meeting, they now ''talk all the time''.
She said: ''He invited me to his concert. And now we talk all the time. I ask his advice.''
While the 'Stranger Things' actress is comfortable with Drake, there's other male stars that still leave her starstruck.
Discussing whether she's changed since she first found fame, she told W magazine: ''I don't think I've changed. I'm not thinking, Oh, I know everything now. I still get nervous. I still get anxious.
''Although, even back then at the BAFTA tea, when I met Justin Timberlake, I swear I could have fainted.''
And Millie could ''barely speak'' when she came face-to-face with her childhood idol, Zac Efron.
Asked her favourite toy as a child, she said: ''A microphone that had 'High School Musical' on it. I could sing with Zac Efron!
''I watched 'High School Musical' every single day. When I met Zac Efron, I could barely speak.''
When Millie first auditioned for 'Stranger Things' in 2015, she had no idea how big the show would be or how much it would change her life.
She said: ''I didn't know anything about it. Every part of the show was top secret. I Skyped with the directors [brothers Matt and Ross Duffer], and we spoke about '80s movies--'E.T.', 'Stand by Me', and 'Poltergeist'.
''I flew to L.A. for a screen test, and the next day I got the job! I was 11.
''We did the show, and I went back home to England. I thought, 'OK, it's a little show. What's next?' And then we came to America for the premiere.
''Three days later, my whole life changed. People went crazy! My followers went up to 1 million in one day.
''Magazines wanted me. One of my goals was to be on the cover of W, and you see? Dreams do come true.''