Brooke Mueller has accused Denise Richards of violating a gag order during her sons' custody battle.

The 35-year-old blonde believes the reason she has been denied custody of her twins Bob and Max, four - who she has with ex-husband Charlie Sheen - is partly down to photos showing Denise with the boys during a school field trip with other celebrity parents, which Brooke insists is giving the impression she is a ''bad mother''.

However, Denise - who has daughters Sam, nine, and Lola, seven, from her previous marriage to Charlie Sheen, and adopted little girl Eloise, 23 months - and Charlie have respected the order in place by not speaking to the media about the situation.

A source told ''Denise staged the photo op to portray Brooke as a bad mother.The field trip the preschool took was to a local farm, and there were other celebs with their kids in attendance also.

''Halle Berry was there with daughter, Nahla, and had her picture taken also. It was a ridiculous claim for Brooke to make because there was no evidence to support her claims. Denise and Charlie have both respected the gag order and haven't spoken to the media about the situation.''

Brooke is currently in undergoing 30 days of treatment at the Betty Ford Center - making it her 20th stint in rehab - and lost a third battle against the court for custody last week when the judge dismissed her request.

It was previously claimed the socialite is rooting for her brother to be guardian of the twins in order to keep receiving $55,000-a-month in child support from Charlie, but Brooke instead insists it is Denise who has only agreed to take on the children for her own financial benefit.

A source previously said: ''Brooke's claims that Denise was only taking care of the boys for financial gain fell flat because the actress signed a sworn declaration that she had refused money from Charlie. Denise's declaration also went on to say that she didn't want any money ever for her care of the boys.''