Sandra Bullock's naked success

(BANG) -

Sandra Bullock thinks baring her bottom made her last film a hit.

'The Proposal' star said she is glad she stripped off for the romantic comedy - in which she starred opposite Ryan Reynolds - because the nude scenes were what helped make it a success.

Speaking about why the movie did well at the box office, Sandra, 45, said: "We had all the right people, the right elements in the right place. But to be honest I think nudity had a great deal to do with it. People liked it."

Meanwhile, Sandra is locked in a custody battle with a porn star for custody of her five-year-old child.

Sandra and her husband Jesse James are fighting his ex-wife, adult star Janine Lindemulder, for sole custody of the former couple's daughter, Sunny.

Sandra and Jesse accuse Janine of being an unfair mom and have also brought to light a recent stint she served in jail over tax charges in their case.

In their application for custody they also state: "While in Janine's care, sometimes Sunny is left alone during the day, while her mother is asleep from drug use."

Star of over 100 adult movies Janine - now remarried to Jeremy Aikman - has, however, hit back at the couple for trying to take her daughter.

She said: "I am the best mother I can be. Yes, I have absolutely made horrific choices in the past. I've had my share of drugs.

"But then there's a huge portion of my life, a 10-year span, where there's nothing - I didn't need it."

The custody case continues.