The 34-year-old - who won six Premier League titles, two FA Cups and the Champions League during his 10-year spell in the Red Devils' first-team - left to join Real Madrid in 2003 before later signing for LA Galaxy in the USA.
However, he never came face-to-face with United during his four-year stay in the Spanish capital - something he says he is thankful for as he had yet to get over the fact that he had left his favourite club.
“When I was at Real Madrid it just never felt right to come back to Old Trafford,” he said in the latest issue of official club magazine Inside United – available to buy now.
“The thought of playing United always gives me that sick feeling because I missed the club so much.
“The first few years away were hard and there were a lot of things I missed. It was the club I always wanted to play for and I loved every minute of my time there.
“I always wish I was part of Manchester United, it’s just in me. Even though I’m not there any more, I’m still a huge fan and watch every game where possible.
“I always want them to do well and be successful because the club still means so much to me."
Having returned to Italy on loan from LA Galaxy for a second time in order to maximise his chances of being picked in Fabio Capello's England squad for the 2010 World Cup, Beckham now has his chance to renew acquaintances with the side he made more than 350 appearances for.
And the Three Lions' most capped outfield player - who admitted to almost crying when the draw for the Champions League last 16 was made - says he is relishing the opportunity to finally run out in front of the Old Trafford faithful again.
“When the draw was made it just felt it was the right time to go back. There isn’t one player I’m particularly looking forward to facing. I’m just looking forward to being a part of it all and savouring the atmosphere in both games," he said.
“Returning to Old Trafford is going to be special and a very emotional night. I’ve spoken to Gary Neville since the draw and we both believe it’s going to be a great tie.”
NEWS: Beckham tearful when Milan drew United
