Mel B lied to a judge in her legal war with ex-nanny Lorraine Gilles ... so claims Gilles in the latest salvo.
Gilles' beef is over the restraining order Mel B got earlier this month, prohibiting the ex-nanny from coming near her for 5 years.
The ex-nanny didn't even attend the restraining order hearing, and now she says it's because she was never served with legal docs, despite Mel B's sworn claim Gilles was handed the docs.
Gilles says she's got proof she was in Kentucky the day of the alleged service. She says what actually went down was that the process server handed the documents to Gilles' husband, which is not legal.
TMZ broke the story ... Mel B has claimed estranged hubby Stephen Belafonte and Gilles had an affair and got her pregnant. Gilles fired back with a defamation lawsuit against Mel B, denying the alleged affair and pregnancy, saying they all had 3-ways for 7 years.