Nicola Roberts has defended Cheryl Cole over her whirlwind marriage.

The 'Crazy, Stupid, Love' singer tied the knot with Jean-Bernard Fernandez-Versini in a secret ceremony last week after just a few months of dating, and her former Girls Aloud bandmate insists the depth of her feelings for the French businessman mean she hasn't rushed into things.

She tweeted: ''For the Versinis', but mostly for her, who is happier than ever. Love. xo.(sic)''.

The message was accompanied by a picture of a quotation which read: ''You can be in a relationship for two years and feel nothing; you can be in a relationship for two months and feel everything.

''Time is not a measure of quality; of infatuation, or of love.''

Meanwhile, Cheryl's new engagement and wedding rings have been estimated to be worth a staggering £300,000 by celebrity jewellery Vashi Dominguez.

The jeweller explained: ''Cheryl has been presented with an emerald cut diamond engagement ring by Jean-Bernard.

''Reminiscent of Kim Kardashian's emerald cut choice following her recent wedding to rapper Kanye West, the ring is

crafted from platinum in a wide band and mounted with two large side stones for that added sparkle.

''Cheryl wears the showstopper with an elegant channel set diamond wedding ring - a popular choice which is understated and sophisticated yet still beautifully eye-catching.

''This bridal set has a value of almost £300,000. I would value the new engagement at £275,000 and the diamond wedding ring at £15,000.

''Jean-Bernard is to be congratulated for his taste - they are two

gorgeous rings and work so well as a combination.''

And Vashi believes the pieces are worth much more than the engagement ring and second ring given to Cheryl by her first husband Ashley Cole - who she divorced in 2010 amid reports of his infidelity.

The founder added:''Originally, Ashley Cole proposed to Cheryl with a sweet heart-shaped diamond engagement ring worth around £150,000.

''After the cheating scandal, he attempted to 'wow' her back and bought her a huge six-carat princess cut diamond ring, with a complementing dazzling yellow diamond halo setting. This set him back £160,000.''