Police said they did not suspect foul play, though the cause of death was not immediately apparent.
Mr Monteith, who had played front man and heart throb Finn Hudson since the hit show began in 2009, had been treated for drug addiction and reportedly had a history of substance-abuse.
The entertainment world reacted with shock and sorrow on Sunday following the death of Cory Monteith, one of the stars of the hit musical series Glee.
The “Finn” ink was brought to light when Lea stripped down for a naked photoshoot for Women's Health magazine.
"[Cory] and Lea make a great couple," Matthew recently said. I will sing at their wedding." It looks like Matthew's planning their special day before the couple even gets engaged.
The new couple are believed to have met through mutual friends and were recently spotted looking close on a dinner date in Santa Monica, California.
The 29-year-old also unveiled two new tattoos – one of which honours her late boyfriend Cory Monteith, who would have turned 34 on Wednesday.
Lea proved that Cory would always hold a special place in her heart by getting an inking of the number five – the American football team his character Finn played for in .