diff --git a/TTS/tts/layers/losses.py b/TTS/tts/layers/losses.py
index 213970a7..7e9304de 100644
--- a/TTS/tts/layers/losses.py
+++ b/TTS/tts/layers/losses.py
@@ -3,6 +3,7 @@ import numpy as np
 import torch
 from torch import nn
 from torch.nn import functional
+from torch.overrides import handle_torch_function
 from TTS.tts.utils.generic_utils import sequence_mask
 from TTS.tts.utils.ssim import ssim
 
@@ -440,5 +441,109 @@ class SpeedySpeechLoss(nn.Module):
         l1_loss = self.l1(decoder_output, decoder_target, decoder_output_lens)
         ssim_loss = self.ssim(decoder_output, decoder_target, decoder_output_lens)
         huber_loss = self.huber(dur_output, dur_target, input_lens)
-        loss = l1_loss + ssim_loss + huber_loss
+        loss = self.l1_alpha * l1_loss + self.ssim_alpha * ssim_loss + self.huber_alpha * huber_loss
         return {'loss': loss, 'loss_l1': l1_loss, 'loss_ssim': ssim_loss, 'loss_dur': huber_loss}
+
+
+def mse_loss_custom(input, target):
+    """MSE loss using the torch back-end without reduction.
+    It uses less VRAM than the raw code"""
+    expanded_input, expanded_target = torch.broadcast_tensors(input, target)
+    return torch._C._nn.mse_loss(expanded_input, expanded_target, 0)
+
+
+class MDNLoss(nn.Module):
+    """Mixture of Density Network Loss as described in https://arxiv.org/pdf/2003.01950.pdf.
+    """
+    def __init__(self):
+        super().__init__()
+
+    def forward(self, mu, log_sigma, logp_max_path, melspec, text_lengths, mel_lengths):
+        '''
+        Shapes:
+            mu: [B, D, T]
+            log_sigma: [B, D, T]
+            mel_spec: [B, D, T]
+        '''
+        B, D, L = mu.size()
+        T = melspec.size(2)
+        x = melspec.transpose(1,2).unsqueeze(1) # [B, 1, T1, D]
+        mu = mu.transpose(1, 2).unsqueeze(2) # [B, T2, 1, D]
+        log_sigma = log_sigma.transpose(1, 2).unsqueeze(2) # [B, T2, 1, D]
+        exponential = -0.5*torch.mean(mse_loss_custom(x, mu)/torch.pow(log_sigma.exp(), 2), dim=-1) # B, L, T
+        log_prob_matrix = exponential -0.5 * log_sigma.mean(dim=-1)# -(hp.n_mel_channels/2)*torch.log(torch.tensor(2*math.pi))
+        log_alpha = mu.new_ones(B, L, T)*(-1e4)
+        log_alpha[:, 0, 0] = log_prob_matrix[:, 0, 0]
+        for t in range(1, T):
+            prev_step = torch.cat([log_alpha[:, :, t-1:t], functional.pad(log_alpha[:, :, t-1:t], (0, 0, 1, -1), value=-1e4)], dim=-1)
+            log_alpha[:, :, t] = torch.logsumexp(prev_step + 1e-4, dim=-1) + log_prob_matrix[:, :, t]
+        alpha_last = log_alpha[torch.arange(B), text_lengths-1, mel_lengths-1]
+        mdn_loss = -alpha_last.mean() / L
+        return mdn_loss#, log_prob_matrix
+
+
+class AlignTTSLoss(nn.Module):
+    """Modified AlignTTS Loss.
+    Computes following losses
+        - L1 and SSIM losses from output spectrograms.
+        - Huber loss for duration predictor.
+        - MDNLoss for Mixture of Density Network.
+
+    All the losses are aggregated by a weighted sum with the loss alphas.
+    Alphas can be scheduled based on number of steps.
+
+    Args:
+        c (dict): TTS model configuration.
+    """
+    def __init__(self, c):
+        super().__init__()
+        self.mdn_loss = MDNLoss()
+        self.l1 = L1LossMasked(c['loss_masking'])
+        self.ssim = SSIMLoss()
+        self.huber = Huber()
+
+        self.ssim_alpha = c.ssim_alpha
+        self.huber_alpha = c.huber_alpha
+        self.l1_alpha = c.l1_alpha
+        self.mdn_alpha = c.mdn_alpha
+
+    def forward(self, mu, log_sigma, logp_max_path, decoder_output, decoder_target, decoder_output_lens, dur_output, dur_target, input_lens, step):
+        # flow loss - neg log likelihood
+        ssim_alpha, huber_alpha, l1_alpha, mdn_alpha = self.set_alphas(step)
+        mdn_loss = self.mdn_loss(mu, log_sigma, logp_max_path, decoder_target, input_lens, decoder_output_lens)
+        l1_loss = self.l1(decoder_output, decoder_target, decoder_output_lens)
+        ssim_loss = self.ssim(decoder_output, decoder_target, decoder_output_lens)
+        huber_loss = self.huber(dur_output, dur_target, input_lens)
+        loss = l1_alpha * l1_loss + ssim_alpha * ssim_loss + huber_alpha * huber_loss + mdn_alpha * mdn_loss
+        return {'loss': loss, 'loss_l1': l1_loss, 'loss_ssim': ssim_loss, 'loss_dur': huber_loss, 'mdn_loss': mdn_loss}
+
+    def _set_alpha(self, step, alpha_settings):
+        '''Set the loss alpha wrt number of steps.
+        Return the corresponding value if no schedule is set.
+
+        Example:
+            Setting a alpha schedule.
+            if ```alpha_settings``` is ```[[0, 1], [10000, 0.1]]```  then ```return_alpha == 1``` until 10k steps, then set to 0.1.
+            if ```alpha_settings``` is a constant value then ```return_alpha``` is set to that constant.
+
+        Args:
+            step (int): number of training steps.
+            alpha_settings (int or list): constant alpha value or a list defining the schedule as explained above.
+        '''
+        return_alpha = None
+        if isinstance(alpha_settings, list):
+            for key, alpha in alpha_settings:
+                if key < step:
+                    return_alpha = alpha
+        elif isinstance(alpha_settings, float) or isinstance(alpha_settings, int):
+            return_alpha = alpha_settings
+        return return_alpha
+
+    def set_alphas(self, step):
+        '''Set the alpha values for all the loss functions
+        '''
+        ssim_alpha = self._set_alpha(step, self.ssim_alpha)
+        huber_alpha = self._set_alpha(step, self.huber_alpha)
+        l1_alpha = self._set_alpha(step, self.l1_alpha)
+        mdn_alpha = self._set_alpha(step, self.mdn_alpha)
+        return ssim_alpha, huber_alpha, l1_alpha, mdn_alpha