Vanessa Hudgens admires the strength of the girls at the pregnancy shelter where she stayed to prepare for 'Gimme Shelter'.

The 'High School Musical' star immersed herself in her latest role as homeless pregnant teenager Agnes 'Apple' Bailey, and spent about two weeks at a shelter learning and observing how these girls lived before they began filming.

Although she initially found the experience ''terrifying'' she bonded with the women over her stay and they helped her understand what they were going through.

She told ''Being in this environment was such a shock to begin with and just knowing that I was going to completely disassociate myself from the life that I'm used to was terrifying. It was really scary for me to be out there on my own. I didn't have any family with me. It really made me get into that mindset and be able to just become one of the girls and in their same circumstance.

''I'm so grateful I had the time to go and stay there because it really allowed their stories to become reality rather than just a story.

''They really opened up to me and they shared their story with me. I just got to witness first-hand how strong these young women are.''

Hudgens realised that these pregnant teenagers have the same needs and wants as any other young adults but they have a much harder life and are easily judged by others.

She added: ''I had never been around girls that young who are pregnant, but it was interesting because I really got to look into their lives and see that they are still just girls, and they have the same needs that any other 16-year-old would have. But due to their situation, it's easy for people to judge and I hate that.''