The deal was done in principle earlier in the day as you can see from the video it light when Lambert signed his shirt with Ken Choo, but it was not made official until around 10.40pm on Wednesday night.
It's been reported that WBA would only sign off on the deal when they had secured the signing of Wales striker Hal Robson Kanu at The Hawthorns.
Lambert has signed a two year deal with the Bluebirds and said
“I’m very excited. I can’t wait to get started," he said.
“It’s been a long day trying to push this through, it’s something that I was desperate for.
“I’m overjoyed.
“I played under Trollope and Lennie at Bristol Rovers - that was a big reason why I pushed this move so much.
“I’m not playing a lot at the minute and what I miss most is scoring goals.
“The sooner I can get on the scoresheet and start helping my new team, the better because I’m used to people relying on me for goals.”
