By GENE STOUT

Marina and the Diamonds – a solo, uptempo alternative-pop act featuring Welsh singer Marina Lambrini Diamandis — will join Coldplay’s worldwide tour, but not soon enough to perform at Coldplay’s headlining concert April 25 at KeyArena.

Diamandis, who simply goes by the name Marina (the “Diamonds” are her fans, she explains), joins Coldplay for a string of summer dates in the eastern United States, beginning with concerts July 29-30 in Boston.

Marina and the Diamonds’ upcoming album, “Electra Heart,” features the sexy new single and video, “Primadonna,” which could turn into a breakthrough hit for the singer born in Wales to a Welsh mother and a Greek father (Diamandis means “diamonds” in Greek).

The album (due in July in the U.S. on Atlantic Records) was written and recorded in London and Los Angeles over the last 18 months while she was on tour. Collaborators included Dr. Luke (who has worked with Katy Perry), Rick Nowels (Madonna), Liam Howe (Sneaker Pimps), Greg Kurstin (Lily Allen) and Diplo (M.I.A.).

“Electra Heart” is the follow-up to Marina and the Diamonds’ 2010 debut album, “The Family Jewels,” which opened at No. 2 on Billboard’s new-artist chart after first being released in the United Kingdom. Marina spent most of 2010 performing at festivals and as a support act on headlining tours, among them Katy Perry’s “California Dream Tour.”

Marina describes “Electra Heart” as “an ode to dysfunctional love. I based the project around character types commonly found in love stories, film and theater, usually ones associated with power and control in love, as opposed to weakness or defeat,” she says in her official Atlantic Records “bio.”

“I guess it was a way of dealing with the embarrassment that, for the first time in my life, I got ‘played.’ Rejection is a universally embarrassing topic, and ‘Electra Heart’ is my response to that. It is a frank album.”

Visit Marina and the Diamonds’ website here.