Fergie joined Black Eyed Peas to become a "better" solo artist.
The 36-year-old singer was "very honest" about her solo career being her main priority, but singing with the 'I Gotta Feeling' group - which includes will.i.am, Taboo and apl.de.ap - gave her confidence in her own ability.
She said: "At first, my ultimate goal was a solo album. I was very honest about that when we became friends. That's why there's never been any resentment.
"I felt I was only going to become a better solo artist by joining them and seeing their world.
"They gave me the confidence to sing a song like 'My Humps'. The confidence to bring out a side of me that I was too shy to show before."
Fergie - whose real name is Stacy Ann Ferguson - also admitted her role in the 'Where is the Love' group has changed to encompass much more than in their early days, when she would take a back seat.
She added to the Daily Mirror newspaper: "I used to hang in the background a lot. I was trying to feel my way into it. There was definitely criticism - 'What's a white girl doing in a rap band?' - but that just made me hungrier and I had the guys' support.
"I learned onstage where I fitted in. It wasn't like we had rehearsals or anything."