The concept of naturalness

[jutfrank]

It happened that I was going there too and I gave him a lift.

In BrE, that's not natural.

I don't see what's unnatural about it. For me, it's fine.

 

[5jj]

It happened that I was going there too and I gave him a lift.

I would be far less likely to say that than I would

either "I happened to be going there too ..." or "It just so happened that I was going there too ..."

or "It so happened that I was going there too ...".