The phrase "already fervent" is correct and usable in written English.
It can be used to describe a state of intense enthusiasm or passion that exists prior to a certain point in time or event.
Example: "Her already fervent support for the cause only grew stronger after the recent developments."
Alternatives: "already passionate" or "already intense".
It is immensely popular, well-supported, and there is already a fervent fan base.
Royce was already a fervent Lear admirer, though his first memory of the man's work was being told by his parents to leave the room whenever All in the Family came on, because it was too adult.
Android Task manager app Any.do already has a fervent fanbase on Android, but now it's hoping to attract similar buzz on iPhone.
That the incident went on to define the band was quite unjustified, as The Von Bondies had already garnered a fervent following as a result of their two-boys, two-girls line-up and growing live reputation.
For a man brought up to believe the world was flat, the Dalai Lama's embrace of science is remarkable, although he was already demonstrating his fervent curiosity for the mechanics of the world when teaching himself to fix clocks and film projectors as a boy in Lhasa.
Kudos to the Kawamoto for crafting some impressive looking hardware (I can already hear some fervent netizens calling on Sony to extend a job offer), and for providing us all with a neat if ultimately baseless (for now) thought experiment.
And of course, there are the VR horror games, which already enjoy a fervent following.
It is a stance that could alienate young, more fervent Muslims already suspicious of Moscow's efforts to limit their religiosity, but it also leaves no doubt how the Kremlin will react to any hint of rebellion within its own borders.
Greenhow was already well-known as a fervent supporter of the Confederacy.
