The singer popped the question to Nareesha - who he has been dating for six years - by hijacking his own surprise birthday party so all the couple's closest friends and family could witness him getting down on one knee.
He explained in an interview with the new UK issue of HELLO! magazine: ''About a month ago I found out Nareesha was planning a surprise party on my birthday with her family, so I thought, perfect! She walked in to plan my surprise and everyone was there already and I was on one knee ready to propose.
''I wasn't nervous until the last 15 seconds and thought, 'My knees are going to give way', I can't remember some of it, the blood went to my head...''
The 'Chasing The Sun' singer had a fright when prankster Nareesha initially rejected his proposal, but he soon realised she was joking.
Siva recalled:''When it came to proposing I had a little speech and said, 'The best gift you could give me would be for you to be my wife'. And she said 'No' and then she said 'Yes'.
''That's just her sense of humour. She's always making jokes like that - but I nearly fainted!''
Nareesha - who met Siva during his modelling days when she provided the footwear for one of his catwalk shows - laughed: ''You have to keep them keen a little bit, haven't you?''
Siva, 25, is sure his Wanted bandmates - Tom Parker, Jay McGuiness, Nathan Sykes and Max George - will be delighted for the couple although he isn't sure if he's going to ask any of them to be his best man.
He said: ''It feels a great place to be in. it's the next step and I feel grown up and mature. It's more of a settled, happy feeling ... I think [The Wanted will] be really happy for us. They've expected it for a long time. They've known Nareesha as long as they've known me.
''I have a big family and am still close to my best mates from back home so I don't even know who'll be my best man. I'm very lucky. My closest friends have been planning my stag for ages, they want to do something geeky because I'm a bit of a geek.''
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