Actress-designer Sienna Miller is reportedly obsessed with model Cara Delevingne and trying to spend maximum time with her.

The 32-year-old actress, who has 11-month-old daughter Marlowe with her fiance Tom Sturridge, has become inseparable with the 21-year-old model and has been pushing away her friends to spend time with Delevingne, reports femalefirst.co.uk.

"Sienna is relentless about wanting to spend time with Cara. She seems a bit obsessed," said a source.

However, it seems Delevingne's close friendship with Miller, who she was caught kissing last year, may be the reason behind the former's split with actress Michelle Rodriguez in April.

"When Cara was dating US actress Michelle Rodriguez, Sienna was always getting involved and it caused an issue. She was always kissing Cara, which Michelle wasn't keen on," said the source.