According to Jensen Ackles, his early days on Dark AngelThese were far from heavenly.
He made an appearance during the Jan. 18 episode Michael Rosenbaum, Inside of YouIt is the Supernatural alum admitted that he and Jessica Alba Co-starring in the science fiction drama of the 2000s didn’t go as planned.

Jensen described his experience as “horrible”, and Jensen said, “I am not kidding.” “I’ve spoken this truth to her face.”

The actor said that he could understand the situation now after looking back. Jess is my love, and that I understand contradicts everything I just said.” he continued. She was subject to a lot of pressure while she appeared on the show. Young, in a relationship [with co-star Michael Weatherly]It was rough and caused some stress, I think on set. 
Jessica was only 19 years old at the time she got the FOX star role. Jensen (23 at the time) officially joined FOX’s series in the second season. This is what he credits for some tension.