Angela Formosa said that she and her taxi driver husband Daniel, 36, were "happy and relieved" to have the girls at home.
She said: "They are really well, they are putting on weight. They are normal bubbly babies who are starting to smile and cry when they want something.
The mother-of-three added that she was "incredibly grateful" to the GOSH staff.
"What they have done for my two girls is amazing. When I was pregnant they were saying that the survival chances were quite low. For them to have been operated on and doing so well - it is amazing."
The girls were operated on by a team of specialists led by paediatric surgeon Professor Agostino Pierro.
He said: "In this case, the twins were joined by the abdomen at the level of the umbilicus and shared part of the intestine.
"The operation to separate the twins had to be performed as an emergency because of an intestinal blockage.
"We are delighted with the outcome of the operation. The babies will need further treatment in the future, but we expect that they will both be able to lead happy and normal lives."
The twin are doing well and have been described as "normal bubbly babies," despite warnings that survival chances were low.
Mother Angela, 32, said: "At an early pregnancy scan they said the twins looked very close together so I went to King's College for another scan.
"Between 16 and 20 weeks we found out that they were joined - I didn't know what to think, I was shocked and I felt sad.
"We didn't know what to expect until they were born - the doctors could not tell where they were connected.
"They decided to deliver them early at 34 weeks. I went into University College Hospital and had the C section and the doctors decided that the girls should go for their operation quite soon, within a couple of hours they had been taken to GOSH.
"I stayed at UCH overnight then discharged myself the next day so I could be with the girls."
A mother has described her joy after a successful operation to separate her conjoined twins.
Rosie and Ruby Formosa, who are only 12 weeks old, needed an emergency operation to separate them after they were born joined at the abdomen and shared part of the intestine.
The identical girls underwent an operation at London's Great Ormond Street Hospital (GOSH) on July 27 - the day after they were born.