The couple, who underwent a civil partnership in 2005, say they are aiming for a "low-key" ceremony in May.In an interview for US TV, Sir Elton said: "We'll do it very quietly. But we will do it and it will be a joyous occasion and we will have our children."Gay marriage became legal in England and Wales this weekend.Sir Elton added: "For this legislation to come through is joyous, and we should celebrate it. We shouldn't just say "Oh, well, we have a civil partnership, we're not going to bother to get married". We will get married."And during the interview, Furnish said of the anticipation from their circle of friends: "The phone's been ringing off the hook."In a separate interview, he said: "I think what we'll do is go to a register office in England in May, and take the boys with us, and a couple of witnesses."The couple have two children, Zachary, who is three, and one-year-old Elijah.