Adam Lambert: Top-earning 'American Idol' alum

Out singer Adam Lambert was the top-earning American Idol alum of last year.

According to Forbes, Lambert raked in $10 million in 2015.

Country singer Carrie Underwood came in second, earning $8 million in the last year. Underwood was the top earner in 2013 and 2014.

"Adam used the launching pad of American Idol very well to have a successful recording career," Martin Kirkup, who co-manages Lambert's career, told Forbes two years ago.

"I think the main part of his career still lies ahead of him," he predicted.

Lambert appeared on the show's 8th season, coming in second behind Kris Allen.

Lambert released his third album, The Original High, and sold out shows as the lead vocalist of the rock band Queen in 2015.

Chris Daughtry ($6 million), Phillip Phillips ($5 million), Scotty McCreery ($4 million, tie) and Kelly Clarkson ($4 million, tie) round out the five top-earning American Idols of 2015.

The fifteenth and final season of American Idol premiered this week.