Estere and Stella, who were adopted by the singer from Malawi two years ago, clearly had huge fun dressing up in colourful costumes and taking a dip in their swimming pool in Portugal. Picture: Instagram

London - When your mother is one of the richest pop stars in the world, you can probably demand a host of expensive birthday treats.

But it seems that all Madonna’s twin daughters wanted as they celebrated turning seven was to be transformed into mermaids, their favourite mythical creature.

Estere and Stella, who were adopted by the singer from Malawi two years ago, clearly had huge fun dressing up in colourful costumes and taking a dip in their swimming pool in Portugal.

Madonna, who famously used actors dressed as mermen for the video of her 1989 hit Cherish, posted pictures of the twins on her Instagram page. They show Estere and Stella in their mermaid costumes and at a ladybird-themed birthday party.

Madonna has two other children adopted from Malawi – son David, 13, and daughter Mercy James, also 13 – as well as daughter Lourdes, 22, with actor Carlos Leon, and son Rocco, 19, with former husband Guy Ritchie.

The singer turned 61 a fortnight ago, celebrating with a lavish party at which she dressed in full military regalia and fishnets.

Daily Mail