Keanu Reeves is embarrassed that he had "the classic 40 meltdown".

The Hollywood star turned 47 in September and found the ageing process difficult at one point.

Keanu has described how he felt when he hit the milestone.

"I had the classic 40 meltdown. I did. It's embarrassing. It was pretty funny. But then I recovered," he told British newspaper The Independent.

"To me, it was like a second adolescence. Hormonally, my body was changing, my mind was changing, and so my relationship to myself and the world around me came to this assault of finiteness. It was also the end of the projection of my younger self. I came to the place where I thought, 'I don't know where I am anymore but where have I come from and what am I doing?'"

Keanu is perhaps best known for his role in the science fiction action trilogy The Matrix. The Wachowski brothers-directed film was a ground-breaking moment in cinema, as revolutionary digital effects were used.

Keanu looks back on the experience with fondness.

"I think you have to because time has gone by," he admitted when asked if he looks at the movie with different eyes now.

"The deeper thing that happened was it was computer generated. It was a digital moment. And that can only be put in the context by the passage of time, generally speaking. John Gaeta, who did the visual effects, knew what was going on, and so did the Wachowskis but I didn't."