Dicks made 326 appearances for the Hammers and was a former team-mate of Bilic at Upton Park.
“To be joining the first-team coaching staff at my club is fantastic news for me,” he told the Hammers’ official website.
Dicks has been at the helm of West Ham’s Ladies side for the past year but will now work alongside Bilic as a full-time coaching assistant.
“I was with the Ladies last year and I thoroughly enjoyed that, but to get the opportunity to work with Slaven, his coaching staff and the first-team players is a dream come true.
“This is a Premier League club with some very good players already in the squad and some more very good players set to come in this summer. It is exciting times for me and exciting times for West Ham.
“I met up with Slaven last week and, although we had not met in person for a few years, it was like we had never been apart. We had a hug and a kiss and sat down and talked all about West Ham and all about football.
“We had a great relationship when we played together in the same team here and I am sure we will work well together again as manager and coach.”
Dicks, who scored 65 goals in 326 games from left-back for the Hammers, said he had watched Bilic???s development as a manager closely during stints with Croatia and Besiktas, and is looking forward to working closely with him.
“Slaven was a top player and he has gone on to become a very good manager,” Dicks said. “His teams play a high-tempo pressing game and I am sure he will instil that style of play here at West Ham.
“I have always said that the first quality that players must illustrate is hard work. If you then have very good players who work very hard, then you can achieve great things and hopefully we can do that here at West Ham.
“I understand that I will be involved on the training pitch and in the meetings and I cannot wait to get down to work with Slaven, his assistant and his other coaches.”