Josh Groban is engaged, and if you’re wondering how his ex, astronaut Katy Perry, feels, she’s getting into it on TikTok. The singer posted a video of herself jokingly crying over the news, soundtracked by “The One That Got Away,” which, yes, she wrote about Josh. FYI, Josh was asked about inspiring the song by Andy Cohen, and explained, “We did [date]. We were both very private, and so we realized we were better as friends. And we’ve been very, very good friends to this day. She's the best. But, I was not expecting that. That was a double take and a spit out my coffee when I saw that. “I listened to the lyrics of the song,” he added. “And I’m like, ‘I never owned a Mustang. I don’t have a tattoo. Are you sure that’s about me?’ We were both very private and we realized we were better as friends and we’ve been very, very good friends to this day. She’s the best.” Reminder that Katy and Josh were together allllllll the way back in 2009, so this is ancient history.…