The 29-year-old DJ asked the 'R.I.P.' hitmaker, whom he has been dating for almost a year, to share his mansion with him in Beverly Hills in a bid to stop their hectic schedules destroying their romance.
Speaking to the Daily Star newspaper, a friend of the couple said: ''It's no secret that there were times last year that they struggled:
''It isn't easy for any new couple to spend weeks at a time away from each other. Over Christmas Calvin asked Rita to move into his LA home full-time so their work commitments don't lead to a break-up.
''He believes they can make their relationship last if they both fully commit to it.''
The 23-year-old singer, who was kicked out of her rented apartment in London last month due to complaints about noisy late night parties, reportedly agreed to move in with her beau, but took her time giving him an answer initially.
The pal explained: ''Rita took her time making the decision. It's a big step after all.
''But she does spend a lot of time in LA anyway and has friends there. So in the end she knew it was the right thing to do.
''Calvin was delighted when Rita told him the answer was yes.''
Take a look back at October's inaugural event.
The film is expected to continue without Mendes' involvement.