Megan Fox is ''very passionate'' about her boyfriend Machine Gun Kelly.

The couple met on the set of their upcoming movie 'Midnight in the Switchgrass' and Randall Emmett - who directed the flick - has revealed the pair are ''very happy'' in their romance, which he described as ''sweet and beautiful'' to see.

He said: ''They're very passionate about one another and very happy, and I mean, it's really sweet to see that I had a little hand in that.

''The chemistry [on set] was second to none, but I just thought, I'm a great director! I didn't know there were these undertones and all that, and now, we spend a lot of time with them since they've been together and it's really sweet and beautiful, and I'm really happy for both of them.''

Randall and his fiancée Lala Kent have been on double dates with Megan and Kelly - whose real name is Colson Baker - and the filmmaker joked the new couple are ''glued to each other''.

He added to 'Entertainment Tonight': ''Let me tell you the joke I make about our double dates, and they know I say this to their face: Going on a double date with Megan and Colson, it's like an individual date and a double date. The first half is very 'double date.' Everybody is conversing, we're having fun, we're laughing. The second half, they don't even know our name. They're just glued to each other!''

Meanwhile, Megan recently admitted in a conversation with Randall and Lala that she knew ''something'' would happen between her and Machine Gun Kelly, 30, on the set of the upcoming movie.

The 34-year-old actress - who has sons Noah, seven, Bodhi, six, and Journey, four, with her estranged husband Brian Austin Green - said: ''I was like, 'Who is going to play this role?' And he was like, 'Oh, we just got Machine Gun Kelly,' and immediately, I was like, 'Uh oh.'

''Yeah, because I knew - I could feel that some wild s*** was going to happen to me from that meeting, but I wasn't yet sure what. I just felt it like, deep in my soul - that something was going to come from that. So then, we met on set.''