Keith Urban's The Speed of Now Part 1 features two mystery collaborations. The country superstar revealed the tracklist for his new album -- with a few missing details -- on Wednesday (Aug. 5).

The Speed of Now Part 1 features 16 songs, with three collaborations among them. At the end of the album comes "We Were," a song co-written by Eric Church that Urban released as a solo single in 2019, but it's the album's first two tracks that have our attention:

"Out of the Cage," the album's opener, features two not-yet-revealed collaborators, while "One Too Many" is billed as a duet with a to-be-announced artist. Whoever they are, their names are all relatively short, especially that of Urban's "One Too Many" duet partner.

Could the duet be with fellow country artist Cam, or perhaps pop star Sia? Urban has never shied away from bringing in out-of-genre collaborators (see: "Sun Don't Let Me Down," from 2016's Ripcord, which features rapper Pitbull and Chic co-founder Nile Rogers). Urban recently shouted out Luke Combs with a cover of his hit "Even Though I'm Leaving" -- was it a clue?

Perhaps one of those mystery collaborators is rising act Breland? The singer and rapper behind the hit "My Truck" recently shared video of himself in the studio with Urban, and Urban has said that he's made some additions to The Speed of Now Part 1 during the novel coronavirus pandemic, so it's certainly possible that the pair's collaboration made it onto this album.

Already, fans have been able to hear "Superman," "Polaroid" and "God Whispered Your Name" from The Speed of Now Part 1 in addition to "We Were." The album is due out on Sept. 18 via Capitol Records Nashville.

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