Word of the record deal was announced as Lambert is making headlines for confirming to Rolling Stone magazine that he is gay.
"I'm proud of my sexuality," he is quoted as saying. "I embrace it. It's just another part of me."
The 27-year-old San Diego native is preparing to work on his debut album, which is due for release this fall, his record labels said.
"To find a talent as exceptional as Adam Lambert is a rare and special event," Simon Fuller -- creator and executive producer of "American Idol," and founder and chief executive officer of 19 Entertainment -- said in a statement. "I am thrilled that 'American Idol' was the platform for the world to discover this brilliant young man. He is unique and unforgettable and a certain star of tomorrow."
"There are no longer any rules in terms of where the world's next superstars may come from," added Barry Weiss, chairman and chief executive officer of the RCA/JIVE Label Group. "We are thrilled to be getting involved with Adam Lambert as we all at RCA Records believe he is one of those rare, future global stars."
"I'm thrilled that we've come to a creative and collaborative partnership and look forward to developing a really exciting album," said Lambert. "We are 100 percent on the same page and are all anxiously awaiting the start of the recordings. It's going to be ridiculous! Get ready!"