Let's hope the Big Bang theory is legit, then!Where to begin...
At the core of a star, pressures are highest (See: Stellar Nucleosynthesis). If there is enough mass, the star will eventually collapse into a black hole under its own gravitational influence. A singularity event occurs in a central relative position, expanding outward, consuming stellar mass and growing the event horizon as it does.
Now, what is happening inside the black hole?
This article shows the pressure contained within a black hole is theoretically equal to the state found just as our very own universe began its ascension to its current state of entropy. It is the contention of many that within a black hole, matter has been compressed to incredibly fundamental states, perhaps absolutely so - and this is where my part comes in.
The interior of a black hole is perfectly relative to itself, meaning time passes within its event horizon. The fundamental particles do not stay fundamental for long; as the black hole expands the matter contained within is no longer relative to dynamics outside of the event horizon. It has become completely contingent on itself, and these fundamental particles are free to evolve as per our understanding of the universe.
Essentially, you could think of a star compressing into a black hole, and at the same exact time that process is kickstarted, a universe undergoes its Big Bang expansion. It's turtles, all the way down.