The 27-year-old pop beauty duetted with the One Direction heartthrob on the track, which was released as the lead single from her movie 'Fifty Shades Freed', and their racy performance on 'The Tonight Show Starring Jimmy Fallon back in February attracted a lot of attention due to their smouldering chemistry.
The pair went on to sing it together at the BRIT Awards - at a time when there was much speculation that Cheryl, 34, and Liam, 24, had been going through a rocky patch - but Rita is adamant that she always kept the former Girls Aloud star's feelings at the forefront of her mind when promoting the single.
Speaking to The London Evening Standard newspaper, Rita said: ''Just imagine being the person in that situation. I obviously tried to respect Cheryl and everything that was going down at the time. I was very professional, as was Liam, and I completely stayed out of it. We had one goal - to promote the single, and we did just that.''
Liam and Cheryl welcomed their son Bear into the world in March 2017 and 1D hunk did admit in an interview with ES Magazine in March that the couple had their struggles.
He said: ''You know, we have our struggles - like of course I'm not gonna sit here and say that everything's absolutely fine and dandy, because of course you go through different things, and that's what a relationship is. ''But we go through them together as a family and that's the most important thing for me. This part of our relationship was never not going to happen, there was always going to be a little bit of tenseness in the way we sort ourselves out, but tell me a relationship in the world that doesn't go through a spot like that? It's about whether you make it through or not, together, is the main point there I guess.''
Rita plays Mia Grey in the trilogy, which are based on E. L. James' best-selling erotic novels, and has revealed she was pitching to get the title track on every film so it was a relief when she got chosen for the final film.
She said: ''Getting the soundtrack came in very last minute - actually when we were filming. I'd sent the song in months in advance, and they eventually came back and said they couldn't get it out of their heads. They said it was the strongest contender and I was like, 'It's about f***ing time! I've only been asking you for five years!'''