Romance has sparked again between Kate Hudson and Derek Hough.

The rumored couple has started quietly seeing each other again over the past month and a half, according to Us Weekly. They recently spent a couple nights rocking out to U2 while the band performed at The Forum on May 26 and May 29.

On the first night, an eye witness caught the 36-year-old Hudson and the 30-year-old Hough lingering in each other's arms. "She hugged him and they kept their arms around each other for a while before actually letting go," the source told Us Weekly.

They also attended the concert with Hough's sister, Julianne Hough, and her boyfriend Brooks Laich. The pro dancer and his date attended the concert alone the second night and were reportedly "inseparable."

After the concert, the "Rock the Kasbah" star and Hough partied with Aaron Paul at The Roxy in West Hollywood and "looked cosy all night," another source told Us. Earlier that day, Hough had dropped Hudson off at her car in West Hollywood.

The couple first made headlines last December when they were caught making out only days before Hudson announced her split from Muse singer Matt Bellamy. She and Bellamy have a 4-year-old son together but had been broken up for some time before the official announcement.

"Despite this, they remain very close friends and committed co-parents," a rep for Bellamy told Us Weekly in Decemeber.