AN: I’m officially back at my mum’s house for Christmas, and it feels wonderful to not have to worry about anything for a while :D
It wasn’t that Tony had been hiding the fact that he had a twin brother, exactly; it was just that nobody had ever really asked before. Their parents had only ever taken one of them out of the house at a time, probably not prepared to watch two tearaway boys at the same time without assistance from The Help, so the press had aways assumed they were the same person.
Greg had grown tired of the lies by the time they became teenagers. He was very business-minded where Tony was more interested in the creative side of the family company, and though he enjoyed his fair share of partying and women, Greg had never had any patience for having his face in the papers.
By the age of fifteen, Gregory had officially taken over the Japanese branch of Stark Industries whilst studying out there. Tony, instead, had been shipped off to MIT “to nurture his engineering gifts”, though he had always secretly envied his brother for managing to effectively emancipate himself from their parents. Their mother had flown out to stay with Greg often, but Howard had left him to it; Tony hadn’t been so lucky.
Greg hadn’t gone to their parents’ funeral.
Tony had thought, perhaps naively, that he and Greg would become closer without their parents there, but instead he had been called in to head SI’s US offices, and Greg had continued on in Japan. They shared the occasional business or Skype call, and Tony received a birthday and Christmas card every year signed in handwriting he knew didn’t belong to his brother.
Most of the time, he could almost convince himself that he didn’t have a brother at all.
Except when he showed up at the tower via helicopter and swanned into the penthouse during Avengers’ movie night like a damn Bond villain.
“Anthony!”
And it might have been close to thirty years, but Tony still remembered his voice anywhere.
“Fuck,” he murmured, freezing up, as the other Avengers immediately scrambled to their feet.
“Who the -” Clint got halfway through his sentence before pausing, and Tony hunched further into his corner of the couch. “Wait, what the fuck?”
“Clone,” he thought he heard Bruce whisper from somewhere to his right, and realised he was going to have to put a stop to this before someone punched his brother in the face (as appealing as that sounded).
Groaning as he pushed himself to his feet, he held his hands up placatingly. In the process, he got his first good look at Greg in close to thirty years; he... didn’t look too bad, considering. His hair was obviously bottle blond, because Tony himself knew that guys their age weren’t rocking their natural colour if it was anything other than grey, and he had a few wrinkles, but overall, he didn’t look too bad.
“Gregory,” he sighed, ignoring the way the Avengers’ eyes snapped from Greg to him. “What are you doing here?”
“You know this guy?” Steve asked, and Tony nodded.
“I should think he’d know his own twin brother,” Greg piped up, and Tony rolled his eyes.
“Twin?” Thor crowed, looking incredulously between the two of them. “I knew not of this -”
“Yeah, neither did I,” Natasha growled, still very much in battle mode. “Explain, Stark.”
“I -” Tony started, at the same time Greg answered, “I’m his -”, and then they both looked at each other irritatedly.
“She meant me,” Tony huffed. “Why would she mean you? She’s never met you -”
“Stark.”
“Yep, anyway,” Tony cleared his throat, and then held out a hand towards Greg. “Avengers, meet my brother, Gregory. Greg, Avengers.”
“Hello,” Greg drawled with a smirk.
“No, hang on,” Clint shook his head. “Am I the only one who feels like they just had a stroke? Since when have you had a twin?”
“Since May 20th, 1970,” Tony replied, and Greg huffed out a laugh.
“Good one, little brother.”
Honestly, Tony wasn’t sure he hadn’t had a stroke.
---
Tony wasn’t jealous. He was a fully grown man - of course he wasn’t jealous. Tony didn’t do jealously, nope -
And then he heard Steve and Greg laughing in the kitchen.
Maybe he was a little jealous.
Greg had only been with them for two days, and he had already done more to seduce Steve than Tony had in two years. They had argued over girls when they were younger, of course, but goddammit, Tony loved Steve. He’d been trying to take it slow, ease Steve into the idea of dating him, and now Greg had come along and completely ruined it.
Tony wouldn’t have minded so much if he thought Greg was good enough for Steve, but he absolutely wasn’t, and -
Who was he kidding? Tony minded either way. He absolutely wasn’t going to stand for this.
“Greg used to lock me in our closet and call me Dopey Stark,” Tony called, bursting into the kitchen.
At the table, Greg, Steve, and Clint all looked up from their breakfasts, bemused.
“Uh... what?” Clint asked.
“He...” Despite everything, Tony could feel his cheeks heating up a little. “He’s mean, is what I’m saying, and - and Steve shouldn’t date him.”
“Date me?” Greg almost choked around a sip of Tony’s coffee. “What on Earth are you talking about, little brother?”
“I...” Tony didn’t really know what to say, feeling his heart drop into his ass. “I...”
“Tony?” Steve murmured quietly, and Tony made himself look at him. His expression was hard to read. “Could I talk to you for a second?”
Tony, suddenly unable to speak for fear of what was to come, simply nodded his head and let Steve lead him out into the lounge where they could be alone.
“Look, I’m sorry,” Tony managed to get out. “I didn’t mean to -”
“Why on Earth would you think I want to date your brother?” Steve asked, a bemused expression on his face.
At least he didn’t look mad.
“I... I just...” Tony took a deep breath. “You’ve been spending a lot of time with him, these past few days, and I understand that he’s got his life together better than me, and maybe you like the blond look, and -”
“I’ve been getting to know him for your sake,” Steve blurted out with a laugh, and then paused. “I... I wanted him to like me.”
“Why?” Tony croaked, very confused.
“Because I...” Steve took a deep breath, but looked determined. “Because I want him to approve of me when I finally ask you to dinner.”
“You...” Tony felt a little light-headed.
“You’ve been hinting at it, I think,” Steve ploughed on, “and I would like to - go out with you, that is. Your brother showed up and I... I must have just panicked. I didn’t want him to disapprove of me -”
“Trust me, Cap,” Tony waved away his concern. “There is nothing to disapprove of. And even if he had... I can’t say I would have cared all that much.”
“Oh,” Steve murmured, and then took a step closer. “Well then.”
And then Steve leaned in and kissed him. Immediately, Tony’s mind shut down and he went limp against Steve’s chest, relief coursing through him as their lips touched.
“Really, Anthony, right in front of the doorway?” came Greg’s voice from somewhere behind him, and Tony pulled away from Steve just long enough to reply,
