Simeone, who had been linked with Romero last summer, lauded his compatriot's personality, defensive work, and ability on the ball.
"I speak from a point of view as an Argentina fan. I admire his personality, his character, his defensive work and his football ability on the ball," Simeone said.
"As a fan of Argentina, I have seen him play more games for the national team than I have for Spurs, but I'm a big fan of him, for sure."
Romero, who signed a new contract with Tottenham until 2029, is expected to play despite Spurs facing a depleted squad missing at least 11 players. His availability comes as a boost for a side fighting to avoid Premier League relegation, with their attention split between survival and the Champions League.
Simeone, however, urged Atletico to maintain focus and play positively despite their commanding 5-2 first-leg lead.
"We need to play the game where it is. There's a three-goal difference; we need to win, and the best way to do that is to score first and put them in a more uncomfortable position," he said.
Atleti are heavy favourites to progress to the quarter-finals, where they would face either Barcelona or Newcastle United. Still, Simeone stressed that Tottenham, led by Romero, would be determined to make the game competitive.
"We want to take the game in the direction we want. We will have our usual intensity, but Tottenham will want to start on the front foot and put on a show for their fans as well," he said.
Tottenham are reportedly pursuing Adam Wharton and are ready to make a push for the Crystal Palace midfielder, as uncertainty grows over their ability to land primary target Sandro Tonali.
The Netherlands are facing a major fitness concern ahead of their crucial 2026 FIFA World Cup Group F meeting with Sweden, with Frenkie de Jong a doubt for the match after picking up a physical issue.
Tottenham have strengthened Roberto De Zerbi's squad with the signing of Netherlands international Jan Paul van Hecke from Brighton in a deal worth 52 million pounds.
New Liverpool recruit Víctor Munoz faces an anxious wait over his World Cup future after Spain confirmed the winger has suffered a fresh injury setback that could keep him sidelined beyond the group stage.
